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FAQs about Hermit Crab Compatibility

Related Articles: Hermit Crabs, Crabs, Marine Scavengers, Fresh to Brackish Crabs,

Related FAQs: Hermit Crabs 1, Hermit Crabs 2, Hermit Crabs 3, Hermit ID, Hermit Behavior, Hermit Selection, Hermit Systems, Hermit Feeding, Hermit Reproduction, Hermit Disease/Health,
FAQs: By species:
Calcinus laevimanus (Zebra, Left-handed Hermit), Clibanarius tricolor (Blue-Legs), Clibanarius vittatus (a common Gulf of Mexico hermit crab), Dardanus megistos (Shell-Breaking Reef, White-spot, Fuzzy Leg Hermit Crab), Paguristes cadenati (Scarlet, Red-Legged), Petrochirus diogenes (a and other Giant Hermit Crabs), & Anemone Hermits, Sponge/Staghorn/Coral house Hermits, Unknown/Wild-collected,

For Anomurans that live in blue houses.

Brittle Starfish Attacked by Giant Hermit       3/31/18
My large (14 inch plus) brittle starfish was brutally attacked by my giant red hermit crab
<Oh, yes; large ones especially are opportunistic omnivores. Will consume most anything they can get their claws on>
last night and during the incident lost the best part of three legs and the ends of two legs, he had also gained a substantial cut from the top of his body round and down to underneath, it has not touched his mouth but his orange insides are on view, he is still moving around this morning and waving for food but I’m worried he won’t survive for long, is there anything I can do to help or should I let nature take its course?
<Mmm; some benefit from moving the animal to a sump, area where others can't get to it, and overdosing (2-3 X) a useful iodide-ate supplement/solution. Am a fan of SeaChem's line here>
I have removed the crab from the tank and I intend to take him bk to the local fish shop as he has over grown my tank anyway. There are also 3 long pieces of the star fishes legs in the tank, should I remove them or will they grow into other stars lol.
<These I'd remove. Just keep the central disc part>
Thanks for your help
Kind regards
<Welcome. Bob Fenner>

A three-part stocking change up- and saving some Hermits lives?       1/21/16
A multi-faceted stocking question for you all today.
Its been three years of happy reefing since I contacted you guys last. Thank you so much for your incredible online resource. I appreciate WetWebMedia so much for all you do.
<Ahh; thank you for your kind, rewarding comments>
I have a 110 pseudo-reef tank (a few varieties of mushrooms and Zoas nothing else size 60"x22"x20") that is bare bottom. It is currently stocked with a Flame Angel, Mystery Wrasse, Single Ocellaris Clown Fish, and Longnose Hawkfish. Since it is bare bottom, I have a handful of Trochus snails (my preference) as my clean up crew but no other inverts. I'm thinking a few big changes I want to briefly run by you. First, I'm thinking about darning and adding sand for aesthetic purposes. If I do that I would love to add a bunch of hermit crabs.
<Am keen for the sand, negative on the Hermits>
I know Hawkfish can be hit and miss with the small hermits (but the Longnose apparently has a smaller mouth and therefore is not as dangerous on this front?- or this internet misinformation?).
<Mis-; Oxycirrhites will pick them out; eat them>
I am mostly interested in the larger scarlet, Halloween, electric blue variety. I have been unable to find if these critter are endangered in such an environment.
<See my (and others) opinions re Anomuran use; archived on WWM.
In addition to the sand and Hermits, I'm thinking of two new additions. I'm pondering a single yellowtail damsel. I've heard Damsels are… difficult fish, which is why I have always avoided them, but I think the rich blue color would be an awesome addition. I have also read the yellowtail is a social species and a single addition may amplify aggressiveness?
<The social Pomacentrids are best kept in small, odd-numbered groupings; stock 3, 5...>
The final addition I am considering is a Melanurus Wrasse (put that new sand bed to use!). I know they are prone to attacking cleanup crew but was hoping if you could shed some light on their behavior towards Trochus and the large hermits mentioned.
<It may well eat these in time>
I also have concerns with a Mystery Wrasse in the tank. Due to the cost and beauty I'll pick the Mystery every time!
Thanks in advance!
<Welcome! Bob Fenner>

Disappearing hermits       12/8/15
Hi guys, how's things?
<Fine Nic; thanks>
I have a quickish question for you today, something that has been baffling me for some time.
I have a 75 gallon saltwater tank. Over the past year or so most of my hermit crabs have completely disappeared...shell and all.
<Quite common... most species folks employ aren't entirely aquatic and they overcrowd.... and many fishes, invertebrates eat them; esp. when they leave their shells to molt
At one point I had 3 significant sized Halloween hermits, many blue legs including one really large one, 2 zebra hermits, two unknown purple hermits, two unknown red hermits and a ton of the little black ones. All I have left now are the two red ones and a handful of small blue legs. I even recently bought two pale tan coloured ones which also disappeared within about 2 days.
I understand that hermits will fight if there aren't enough shells, but since I have plenty of shells in various shapes and sizes, and since I've never found an empty shell (I knew exactly what the big Halloween hermits were wearing) or body parts I can't see this being the case. They have literally disappeared into thin air.
So my question is, have you ever heard of someone else experiencing this?
<Oh yes>
Is there possibly some type of carnivorous crustacean that could be hiding in my tank that would only target hermits, dragging the shells under the rock?
<Yes; and worms>
As far as I know there is only one single place in the tank (under a large rock) that I can't see from one side of the tank or another.
The only fish I have are a female maroon clown
<Mmm; might be the perp.>
and 3 azure damsels (who lay eggs daily by the way!).
Hopefully you can provide me some clue as to where they are going! I would love to get some more but I need to know why they are disappearing first!
Thanks so much in advance!
<I'd review what's posted on WWM re undesirable hitchhikers, and try baiting, trapping the culprit... using various baits, including hermits.
Bob Fenner>

Re: Disappearing hermits... The Polychaete "did it"!         12/10/15
Thanks so much for the reply Bob. I did as you suggested and read all about undesirable hitchhikers.
<Ah, good; and?>

I've never heard any clicking in the tank so I'm doubting it would be a mantis or pistol shrimp.
I started thinking about your possible worm suggestion, and remembered I had seen 2 fairly large bristle worms many months ago. So I've spent the last few mornings while the lights were still out trying to find them with a red light. Well this morning I discovered one, and when I changed the light from red to white I noticed he is a very pale colour but very
<Yeeikes! I see it in your pic!>
The attached photo is not mine but it looks exactly like what I've found.
He's pretty big from what I can tell. Is it possible this is the culprit who is causing all my large hermits to disappear?
<Oh yes>
I forgot to mention earlier that it's only the smallest hermits I have left.
<Ahh; even more sure>
If it is the bristle worm eating them would he be dragging the shells (some of them 1.5 inches across) under a rock as well?
<Definitely. If you look in its lair, you fill find them there.... onomatopoeia!>

Or should I be finding empty shells still? That's the part that really baffles me, not finding empty shells or body parts.
Please let me know if you think this guy is the culprit and I will attempt to remove it!
<Yes; see/READ on WWM re baiting, trapping these bristleworms out, and DO BE CAREFUL re getting stuck (in your hands) by their podial spines! Bob Fenner>


Banana wrasse Butler (and missing Hermits); w/ a nod to Peter, Paul & Mary     9/23/15
Hi team
<Hey Jim>
I have a lovely banana wrasse in my reef tank. The family picked it (ok I was coerced)
Haven't seen a hermit crab in months.... I seem to remember them being hit and miss when it comes to inverts. Any ideas guys?
<"Where have all the hermits gone? Long time learning....Gone to Halichoeres everyone; when will they ever learn, when will they e..ever learn?"
Thanks Jim
<Cheers, Bob Fenner>
Re: Banana wrasse     9/23/15

I knew it.....that said he is a very happy / good looking fish.
<You bet your wrasse; er, Labrid>
Will have to catch him if I want any cleaner shrimp though.
<Ah yes. Bob Fenner>

Hi Bob,

I think I might be having a problem with one of my hermit crabs. About a week ago, I got another 4 hermit crabs for my tank, making a total of 6. The four new hermit crabs are larger than the two that were already in residence.

As soon as I put the new additions in the tank, one of them got out of his shell and tried to beat the living daylights out of the other new one. What is strange is that they came from the same tank from my local shop, and they were not displaying that kind of behavior there.

So a few days passed and then I found the aggressor dead and a few legs from another hermit crab spread around the tank, so I guess one of the hermits is systematically destroying it's tank mates. Is this a common occurrence among hermit crabs or do you think that this one (don't know which) is just a rogue?

Russ Davies

What can I say or write re the 'opportunistic omnivorous habits' of these Anomurans ('false crabs'). Like their true Crab/Decapod brethren, most Hermit crabs are given to almost constant bickering for shells, and most of them, not just occasional rogues, consider their fellows to be the choicest food items about! What you describe is more the standard than exception re these animals' behaviour. Given the chance or drive from hunger, they gladly pull their own kind out of their shells for new homes or meals.

Please forgive my bluntness here, but I have been forever querulous re the promotion of Hermit Crabs for almost all marine aquarium applications. They are none of them entirely herbivorous, and given time, 'cross over' to picking on, consuming other invertebrate life. I stand by my admonition re their use, and encourage folks, that if they must add them, to keep their numbers to a minimum. The vast majority of 'clean up tasks' that one might wish to use Hermits for, are better looked after by more careful maintenance or other life forms.

Blue knuckled hermits     11/24/13
Thank you for your help on the mandarin. I have one last question are blue knuckled hermit Crabs safe with Asterina starfish?
<Calcinus elegans will usually leave all else alone other than algae of various sorts.
If hungry; all hermits will "cross the line" and consume other life. Bob Fenner>

Hermit Crab and Nudibranch: Clibanarius cruentatus and Aeolidiella alba, IDs, comp. – 11/13/12
> Hi,
> <Hello, Lynn here this morning.>
> I recently brought 2 'Mexican algae hermit crabs' that were supposed to be reef safe, one of them I cannot identify the species... Any idea?
> <Yep, it appears to be Clibanarius cruentatus, aka the “Spotted Black Hermit crab”, which is in the family Diogenidae (left-handed hermits). Whether this species is completely “reef-safe” depends on your definition of the term. Hermits are typically omnivorous but can have tendencies toward being either more herbivorous or carnivorous.  What's important is that if/when their preferred food dwindles, and they get hungry enough, they will likely “sample” whatever else is available. Bottom line: keep an eye on any and all hermits - even those labeled as reef-safe, algae-eaters, or herbivores.  That is, watch what they tend to eat, make sure they have enough, and monitor for any damage to livestock.  It’s a good idea to supplement their food with meaty bits of marine origin, sinking pellets, and/or bits of Nori (dried seaweed sheets).  Please see the following link for more information and photos regarding Clibanarius cruentatus: http://www.wildsingapore.com/wildfacts/crustacea/othercrust/anomura/hermit/spottedblack.htm 
> More information on hermits here: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm?h=  >
> Also found a Nudibranch on my live rock which I cannot identify.  He doesn't seem to have touched my corals.
> <That’s good to “hear”/read but do keep an eye on them as sometimes the damage isn't immediately apparent. You have what appears to be a species known as Aeolidiella alba (family Aeolidiidae). If you can get a close look at the base of the rhinophores (the knobby-looking appendages just behind the head), you should see either a fine reddish line, ring, or splotch (see photos at links below for comparison). Also reported, is this species’ odd appearance during locomotion as it “waves” or “jerks” its cerata (appendages along the back) back and forth.  Unfortunately, I wasn’t able to locate any information regarding the animal’s diet, but rest assured, it’s a carnivorous predator. These Nudibranchs tend to hitchhike on or near their food source so if your individual arrived on a recent coral addition, I’d remove it asap, and keep an eye out for others.
> Please see the following links for photos and more information:  http://www.seaslugforum.net/showall/aeolalba
> http://seaslugsofhawaii.com/species/Aeolidiella-alba-a.html 
> More information on Aeolids here: http://www.wetwebmedia.com/MolluscPIX/Gastropods/Opistobranchs%20Sea%20Slugs/Nudibranchs/nudibran5.htm?h= 
> Take care,
> -Lynn Z>

Re: Hermit Crab and Nudibranch: Clibanarius cruentatus and Aeolidiella alba – 11/13/12
<You’re very welcome.>
..he came with my live rock which had 1 single Zoa and a single mushroom as hitchhikers. I let the rock cycle and he is still alive and the Zoa and mushroom are fine so I don't know what he could have been eating to live.
<Based on what seems to be the common theme within this family, I’d say a Cnidarian of some sort. Every Aeolidiella species that I was able to find diet-related information regarding, listed one/several varieties of anemone as being their prey of choice. Interestingly enough, other genera within the family (Aeolidiidae) listed hydroids and Palythoa in addition to anemones so that adds to the list of possibilities. Whatever the prey, it’s possible that there may still be some small/hidden individuals left that are sustaining your Nudi. On the flipside, if it has already gone through the food supply, you will likely see the animal roaming about the tank for a short while, then one day it’ll just disappear. Take care, Lynn Z>
Re: Ahh, excellent as always. B – 11/13/12

Thanks Bob, it was a pleasant surprise to see that query in the inbox this morning.  I check in every day, looking for ID's but must be missing them.  
At any rate, it's always a pleasure to see what neat little critters end up in people's systems!
Take care and thanks again,

Hermit crabs... rdg.     6/18/12
Hello there my family recently took a trip to North Carolina and on a crabbing trip my son caught a hermit crab.  Being a 6 year old little boy he wanted to take it home for a pet. Me being me I said ok but now have a few questions, actually a lot, as to habitat and if the wild crab will do well with store bought crabs.  My daughter got jealous and now I am the proud owner of a few of the fun little creatures. I didn't know if the wild crab would attack the tame ones
<They'll all eat each other given hunger, opportunity>

 and if I had to have a different habitat for the water dwelling crab versus the land dwelling store bought ones any help would be greatly appreciated thank you in advance.
<... read here: http://www.wetwebmedia.com/FWSubWebIndex/terrhermitself.htm
and the linked files above for both terr. and marine hermits. Bob Fenner>

Dardanus megistos in a 29gal setup: any possible tankmates?   4/8/12
Hi Bobster!! Apologies if you're getting this question twice from me; I'm having some technical issues here today...lol!
Chris and I are in the process of moving and I am contemplating turning my historically FW or BW 29gal tank into SW. Being me, I can't just pick "normal" fish (Chris' words, not mine!) as potential stock, instead having become enamored with the awesome Dardanus megistos crab.
<Gets big and very mean>
 I've read the FAQ's on the subject as well as your hermit crab article; you say that "aware", quick-swimming fish such as Basses and Lionfish can co-exist with Mr. Hairy;) What about any ideas for tankmates in a smaller system that obviously doesn't leave room for either of those two options?
How about a Diadema Dottyback? Or a wrasse? Or a damsel, such as a Dascyllus or even Amphiprionae? Curious to know your thoughts on this!
Hope you're doing well...hope to see you sometime in the not to distant future!
<Hey Jor... I'd place none of these w/ said Hermit... too likely to become dinner... eaten while they sleep. BobF>
Re: Dardanus megistos in a 29gal setup: any possible tankmates?   4/9/12

Any suggestions for tankmates in a 29?  What about others of the same species?
<Nah; will end up w/ just one. BobF>

Ph <steady> and hermit crab <comp.> help 2/3/12
Hello Wet web Crew,
Thanks for your help with my last issue. I have two more questions though. I bought "Blue Leg" Hermit Crabs from my LFS a few months ago and two of them are definitely not blue leg hermits crabs, at least I think.
The two I am concerned about are huge compared to the other crabs I have and don't even have blue legs. Is it common for other species of Hermit Crabs to be miss labeled as Blue legs? I have read in many places that large hermit crabs are dangerous to my tank especially small inverts. I have a few small Nassarius Snails I am particularly worried about. Should I remove the crabs in question from my tank? Or just wait and see what happens?
<The latter is what I'd do>
And also my pH seems to stay at about 8.4 even after water changes.
<Lucky you. Is fine>
Everyone in my tank seems fine though, I have yet to loose <lose> anyone besides a snail and a hermit crab over the course of 3 or 4 months. (Knock on Wood) Should I try to lower my pH or is about 8.4 okay?
Thanks again,
<Enjoy it while you can... aquariums are reductive environments... Will drop, lose alkalinity in time. Cheers, Bob Fenner>

Snails eating red legged crabs! 10/1/11
Hello to Everyone!!
<Hello Amanda>
I have used your site for all the information that I have ever needed regarding my tank and would like to say thank you so very much again.
<Thank you for your very kind words!>
However, I do have another problem that I can't seem to figure out or find the answer to...I recently bought a new clean-up crew after moving 90 miles and losing some crabs, snails etc. Everyone seemed to be getting along fine, until the other day I watched a Nassarius snail chase down a red legged crab and pluck him from his shell.
To my amazement every Nassarius snail in the tank surfaced and created a "feeding ball," if you will.
Obviously, the poor little crab died and was eaten, but since this instance it has happened two more times. Is this a common occurrence with these species?
<These snails are in the main detritivorous scavengers, but in the absence of sufficient food can turn carnivorous. They are not herbivores, so this is possible, yes>
Can I expect all of my crabs to be eaten by the
Nass. snails?
<Perhaps you should try feeding the system a little more, obviously with an eye on your nitrates et. Al>
Please let me know if there is something I should have done or if there is anything that can be done....I have had these species together before the move quite peacefully with nothing like this ever happening. Thank you again for the great site and advice!
<No problem>
Best Regards,
<<Sorry Amanda, I meant to say they are Omnivores, they will graze but can also be opportunistic!>

baby star fish, and Featherduster worms... missing, eaten? 7/10/11
A few weeks ago my 20g marine tank bloomed into life. There was about 25 baby star fish in the cracks of the rocks, but now all of them seem to have disappeared along with my two baby Feather Dusters that started growing. My tank has one Clarkii Clownfish, two Camel Shrimp, a Blue Leg Hermit Crab, and a Red Leg Hermit Crab. My question is, is it possible that one of my crabs or shrimp ate the Feather dusters or the Starfish? Thank you, Morgan
<Oh yes... more likely the <Hermit> crabs. Bob Fenner>

Bubble Tip Decimated by Hermit Crabs 6/8/11
Good evening,
This past year, I have searched topics that have come up while learning about the care of my saltwater inhabitants and have always come back to your articles.
This time, I have an issue I'm hoping you can help me with.
<Let's see>
I purchased a beautiful Rose Bubble Tip Anemone that arrived yesterday.
Was doing well, acclimating fine. Today, I came home from dinner to see three hermit crabs feasting on it. Most of the bubbles are gone but it is still alive.
Is there any chance of this anemone surviving and what can I do to help?
<There is always a possibility... Have seen this tissue grade life "resurrected" w/ little left. I would treat w/ an iodide/ate compound to high concentration>
<Welcome. Bob Fenner>

Hermit Crabs/Compatibility 4/15/2011
<Hello Rick>
I recently caught a salt water hermit crab. I put it in his own salt water tank. He is eating and doing well. He has some barnacles on his shell. I have a 180 gallon tank I would like to put him in to - It's a fish only
tank. I don't want to make my other fish sick or die. What do I have to do about the barnacles or other parasites the hermit crab may have, before I put him into the tank.
<The barnacles won't last too long without being fed frequent feedings of planktonic food.
As to the crab, all depends on what type it is. Some can grow quite large and are/can be predaceous
toward small fish and other crabs/invertebrates.>
Any information you have would be very helpful.
<Ditto. James (Salty Dog)>
Rick Champon
Merritt Island, FL
Re Hermit Crabs/Compatibility 4/15/2011
Hi James-
The hermit crab is quite large. his shell is about 1 1/2 to 2 inches long.
The tank has large fish say 4 inches and up. tangs, snapper, wrasses, French angel etc. This tank is 500 gallons, and is 4 feet deep. I caught it in Florida, Banana River. I feed him shrimp pieces, and seems to be doing well after the first week. I just don't want to contaminate the tank of the fish I have.
<Is understandable to be cautious, but I do not believe there is too much danger of contaminating your tank with any parasitical disease. But if you want to be on the safe side, leave the crab in it's present quarters for at least two to three more weeks. You will also have to provide larger shells for the crab as it molts/grows. James (Salty Dog)>
Re Hermit Crabs/Compatibility 4/15/2011- 4/16/2011

Ok thanks for your advise.
<You're welcome.>
I'm getting new shells for him now-- one more question - is that the same advice for a snail I caught?
<Sure. James (Salty Dog)>

micro brittle star vs. red legged hermit 4/5/11
Hi folks. I have a 10 gallon reef that is 6 weeks old.
<"Small volumes are very hard to keep stable, optimized... successfully for long">
I started with live sand and 10 lbs of live rock. Two weeks ago I added 1 turbo snail, 2 blue legged hermits, 1 red legged hermit, 2 Cerith snails and 1 Nassarius snail and another piece of live rock, approx 1 ½ pounds.
<I'd take (stocking) things a bit slower>
This latest addition of live rock came with about 3 or 4 micro brittle stars. Tank param.s are: temp 78F, SG 1.024, Ammonia 0, nitrite 0, nitrate 0, pH 8.2, calcium 360 ppm,
<A bit low... best to do water changes here...>
phosphates 0, Alk 9.
Two days ago the red legged hermit found a dark quiet spot in between two small Syconoid sponges. Let's call him/her a him. This morning, over a period of about 2 hours, he has been molting. Then he was sitting on the outside of his shell for about 15 minutes. I noticed a micro brittle star �moving in� and �exploring� with its tentacles. As the crab went back toward the shell opening, the brittle star followed him and that was the end of my red legs. I wasn't aware that micro brittle stars might go after a seemingly healthy crab. Is this true?
<Yes, tis>
Because this is a relatively new tank, could the brittle star not be getting enough to eat?
<Doubtful w/ all the LR>
(I did have the initial brief Cyano outbreak and diatoms and minor hair algae but all has been taken care of by my �crew.� I have not fed the tank at all yet.).
Should I feed the brittle stars to protect my other crabs/snails?
<Not likely to work over time... With molting, the hermits will likely be meals>
Thank you for all you do. Janet
<Welcome. Bob Fenner>

Falco Hawkfish, 10/18/10
I sifted through all I could find about dwarf blue leg hermit crabs and Hawkfish living together in a 55 gallon.
<They will live together fine... until the Hawkfish gets hungry,>
All I found was the person who said their Hawkfish doesn't bother the crabs but focuses on the shrimp they had in tank.
I recently bought some hermit crabs with red legs very tiny (sorry cant recall the name) from my local petstore put them in the 55 and immediately the Hawkfish knew what they were watched them and pecked at their shells. So I put them in my soon to be 14 gallon Nano reef for now.
<Will not be able to house these long term with the Hawkfish, he will eventually consume them.>
If I order some blue legged will he do the same?
Can he actually get them out of the shell?
Is it stressful for the crabs to the point of killing them from stress?
<More likely killing them from attack/consumption.>
Any advice would be greatly appreciated
Thank you in advance,
Jerry Mitchem
<See here for more http://www.wetwebmedia.com/hawkfshcompfaqs.htm .>

Hermit Crab Release in Texas 8/10/10
Can a pet hermit crab be safely and successfully released into the wild anywhere in Texas?
<No. It is not only illegal but also massively irresponsible. Pet releases have causes huge amounts of environmental damage. Here in Europe what we call wilderness was largely destroyed thousands of years ago and is now more or less domesticated. But in the US you still have something that might, with a certain stretch of the definition, be called wilderness.
Please keep it that way. Cheers, Neale.>

Grab bag of questions, hermit crab comp.... 7/24/10
Ladies and Gents,
I have a few disparate questions that I wanted to pose (hopefully not impose upon) to the crew.
DT 52 gal FOWLR starting to turn reef (have GSP and two Zoa colonies) running for 2+yrs. PO4 0.25, NO3 0 (and all parent compounds 0) pH 8.25, Temp 76-78, SG 1.025.
All of that may not be pertinent, but I know how important a good history can be. We have a single blue-legged hermit crab (Hermes)
<I see this>
who has been in the tank for as long as it has been cycled. We recently bought (in March, tank was FOWLR) two more BLHC and initially added to the DT until we kept finding Hermes was pulling the smaller shell of
the crabs into his.
We were concerned for their safety so moved them to our 12 gal QT.
Months go by and we upgraded to a 14 gal Biocube as a new QT since it has better lighting than our previous 12gal. We were shutting down the 12, moved one of the small crabs to the 14 gal and the other to the DT. My fiancé© found Hermes with the other blue-leg's shell pulled up to his and she said she saw him tear off one of the smaller crab's legs and eat it, or some such violence. Apparently he had been holding on to the shell and munching away (or trying to) for several hours when I got home. I separated the two shells and put Hermes into
quarantine. The small crab is still alive and was wandering around the DT the next morning.
I was under the impression that BLHC are reef safe and scavengers.
<Uh, no. Are not as opportunistic as most decapods and the false crabs called hermits, but can/do "cross the line" eating each other if the occasion presents itself>
We use a variety of foods (krill, Mysis, frozen carnivore cubes, pellets, flakes) so I assume that Hermes isn't underfed, but that is the only conclusion I can reach as for why he would turn cannibal. In the tank we also have 2 scarlet leg HC, 2 emeralds,
<... these as well. Please learn to/use the search tool, indices on WWM; read ahead of writing>
2 Turbo snails, 3 Astrea, 3-4 Cerith, and up to 6 Nassarius, but have never seen him attack any of those critters.
<They will in time; particularly if/when hungry>
The first attached picture is of him caught in the act. Should I retire him to a tank of his own or the sump I'm working on? He seems to have become a repeat offender.
<Up to you>
Second query involves a feather duster worm that we purchased a few months back that had a piece of what I believe is a Halimeda sp. attached to his tube.
Pics 2 and 3 are 10 July and 23 July and as you can see, the algae is growing well. I have been entertaining the idea of extricating the algae and placing it elsewhere in the tank or perhaps in a sump when I get one made. I was going to use a scalpel (11 or 15 blade) to cut close to the tube when I remove it. Would it be better to try and get as close to the tube as possible and run risk of cutting it or should I try and trim the algae at a branch?
<Either way... the Green algae is not deleterious...>
Fourth pic, base rock starting to grow diatoms and what appears to be a light coat of fur. Assumption that this is filamentous algae and nothing of concern as it will be overgrown later.
<Likely so>
Fifth pic, last question. This is the side of the new 14 gal QT. Has been set up and running for over a month, some trace NH4 on Seachem disc kit, but 0 NH3, 0 NO2, 0 NO3, pH 8.3, T 78, SG 1.024.
Inhabitants are one BLHC from before, a peppermint shrimp that we added to combat some Aiptasia inherited on LR, a brittle star (oddly enough, with 6 legs...perhaps asexual repro?)
<Mmm, there are Ophiuroids with six legs>
a couple of amphipods, Spionid worms on LR, Red Gracilaria, and these wormesque creatures attached to the tank glass. Any idea what they are?
<Likely some small Polychaete species. I wouldn't be concerned re>
I imagine they are not going to pose a threat and will likely go away before long.
<Well put>
Guess it was more curiosity than anything else.
Last pic is of brittle star before he was moved to other tank. The three smaller legs are now much larger. Sorry for being so wordy and thank you for your time.
<Thank you for sharing. Bob Fenner>

Scarlet Reef Hermit Crab Question/Hermit Crab/Compatibility 6/30/10
<Hello Camron>
I am planning a 12 gal. saltwater tank. I currently have 3 saltwater snails (a Nassarius, a Cerith, and a Nerite) in a temporary 1.5 gal. tank (until I get the 12 gal. set up). I plan on placing these snails in the 12 gal. tank with 1 Tailspot Blenny.
<Ah, one of my favorite blennies.>
With the snails and the blenny in the aquarium, would there be room to include 1 scarlet reef hermit crab?
<Certainly, and is a peaceful crab if you are referring to Paguristes cadenati.>
I am interested in this species because they are not as "aggressive" as other hermit crabs (or so I have been told). Would I have room for the Scarlet Reef Crab, the 3 snails, and the blenny in the 12 gal. tank? Or would I be overstocking?
<You would not be overstocking.>
Thank You.
<You're welcome. James (Salty Dog)>

Unknown Anemone 5/19/10
Hi! This is my first time to ask a question here (I've pored over your site, though), so apologies if I mess up on protocol. You guys have a great site.
<Thank you Daniel>
First off, I live on a tiny little island on the equator in the middle of the Pacific; hopefully that helps for the ID. Recently, I got a Pagurus sp. (pollicaris or some visually similar species). Hitchhiking on its shell were a group of three anemones (I think they're anemones).
<Polyp/oid animals of some sort...>
I've attached a pic, I hope it's clear enough and small enough. These anemones are on the underside of the shell, so does that mean they don't need much light?
<Likely so>
Could you help ID this for me?
<Mmm... perhaps a Calliactis species... maybe C. armatus>
Not sure how well you can see it in the pic, but they have distinct feet and pretty wide bases. Also, could you give me a brief description of their care needs, like if they can take small chunks of food, how much light, etc.?
<Are very likely opportunistic feeders on whatever the hermit is tearing, consuming itself... Not much reliant on photosynthesis as you speculate>
I've kind of grown attached to them, so even if they are Aiptasia (my best guess) or some nuisance anemone, I'd keep them in their own tank. They currently are in a quarantine tank, just in case.
The end destination for this group is a tank lit for fish/crabs, not coral, unless the anemones need bright light, in which case I'll get a new tank and upgrade to the necessary lighting. However, if these anemones can survive in fish lighting, they'll be sharing the tank with a red hermit crab. This guy is the other attached picture. The colors are not exactly true; the crab is lighter and reddish. Is this crab compatible with the anemones, or will the crab snack on them?
<Might consume them if very hungry... But likely to actually move them to new shells with growth, time... they provide protection against predation>
Thanks much for your lifesaving help,
<Thank you for sharing. Bob Fenner>

Red Reef Hermits/Hermit Crabs/Feeding 5/12/10
hi hope you can help
<Hello Mark>
Have read some of the stuff on your site about the red reef hermits, I have 2 of them and they seem to eat nearly every thing on my live rock leaving it barren. Is this normal?
<Can be, they are opportunistic feeders.>
If so should I get rid of them (tank only a week old) I can't find any other mention of any one else having same problem. any help would be greatly appreciated.
<Problem here is that there is little or no food present beside what is present on the rocks and is why they are being stripped. Tank is too new to add scavengers. I would return/relocate until your tank becomes aged a bit or feed the crabs a few times per day with pelletized type food.>
<You're welcome, and in future queries, please, no text type messages. Please cap beginnings of sentences, "i's", and proper nouns such as your name. Saves us time if we do not have to do it before posting. James (Salty Dog)>
Mark Smith

hermits eating Birdsnest 4/21/10
Hey there Crew!!!!!
What would all of a sudden make hermit crabs infest and devour a 6 inch by 5 inch Pink Birdsnest?
<Hunger, awareness, perhaps a "weakened" state sensed re the Seriatopora>
This Birdsnest has been in the same place for 2 years and was doing awesome until 3 days ago. All of a sudden dozens of hermit crabs started eating it. I took out all the hermits that were eating it, any other hermits I could see at the time and did an iodine dip on the coral and put it back in the tank. The next morning it was infested with 15 hermit crabs again. I know hermits are omnivorous and will sometimes eat corals.
<Oh yes>
This tank is 180 gallons, established for over 2 years. I test for 14 different parameters and they are all within acceptable range. The tank has probably 50 or more SPS corals in it and the crabs aren't bothering anything but this Birdsnest. What might the Birdsnest have acquired to all of a sudden make it a magnet for hermits?
<Mmm, can't tell for sure, but "something" changed re making it attractive as a food item>
No other corals or fish have been added to this tank in over 3 months.
I've done a microscopic analysis on the dip water to see if anything came off of the coral and didn't find anything that would point to the cause. There was very little detritus, no algae spores, no worms, parasites or eggs that I
could detect. I've done analysis on problem corals before and found detritus and algae to be a primary cause of what is generally referred to as RTN with a secondary cause the bugs that tend to populate in the detritus causing the loss of coral tissue. I've never seen RTN without finding one or more of the problems previously mentioned. I even did an RODI dip on a branch and didn't find a single thing in the RODI water under the microscope. I'm just perplexed. I've never seen herds of hermits all of a sudden attack and kill a particular coral like this. Any ideas on
what would cause them to do this? I'm attaching a picture of my poor Birdsnest. I moved it to another tank without any SPS in it until I can frag what I can of it and pray I can salvage a branch or two.
Any information you could give me would be appreciated so maybe I can prevent this from happening to any of my other corals. I will continue to remove all the hermits I find. You guys are awesome!!!!
Thank you,
Sandra P.
<Other than my usual warning/admonition re the use of "Hermits", I don't know what changed here. I salute your promptness, actions in effort to save this colony. Bob Fenner><<Mmm, might have been weakened by the GSP below it...>>

Blue Striped Hermit Crab/Compatibility 12/9/09
Good day Bob n crew,
<Hello Blesson>
Upon searching on the internet I believe the hermit crab I have is a blue striped hermit crab (Clibanarius longitarsus). Is this reef safe?
<No crabs are really reef safe as they are opportunistic feeders, and if food isn't easily available, they will go after other items on the menu.><<Or Anomurans, False Crabs. RMF>>
So far it has tried unsuccessfully to get at the snail which I think is a conch of some sort.
<Crab is likely seeking a new bed and breakfast.>
Caught him trying to tear open a fan worm today. Sort of concerned. I already tried searching the faqs area and was unsuccessful. Pls do advise.
<My advice, when in doubt, remove.>
thank you.
<You're welcome. James (Salty Dog)>

Question for the experts. Hermit, snail in/comp. 11/3/09
Thank you so much for your informative website, and generous dealings with newbies to the saltwater/reef hobby. About 3-4 weeks ago, I went to PetCo (I prefer my LFS but they are the only place open after 6pm...) and bought two pieces of live rock, transferring them to my 20g aquarium. I didn't notice anything until about 2 weeks after I had the rocks, when I turned the lights off. There were several tiny, maybe half to 3/4 the size of a dime snails that didn't look anything like the other snails Petco had advertised! I had a suspicion that they were something unusual, and did some research.
Although so tiny that one would need a good magnifying glass to see details, the shape of the shell is pretty textbook. So I really enjoyed having these little guys, as they were the only moving thing in the aquarium big enough to watch! I went out of town for 5 days over thanksgiving, and forgot to tell my boyfriend (who was taking care of my freshwater thank) to watch the water level on the saltwater. When I got back, I thought the evaporation might have caused high of salinity levels, and wasn't sure what would have become of the abalone. A day or so later I saw one empty shell on the sand, and sadly thought all of them must have died. Then in a couple days I decided that since the aquarium levels were all good (0's on phosphate, nitrites/ates, ammonia) I would get some hermit or Mithrax crabs as "janitors". I purchased two "red legged" hermit crabs yesterday. Then yesterday night after turning off the lights, what do I see but the two little abalone I had thought were dead! So my big question is this (and I'm sorry if this was too long-winded of a message but I wanted to be clear):
Do the abalone have any chance of escaping the hermit crabs?
<Mmm, some, yes. If the Hermits are well fed...>
I have found on your website and others that hermits are voracious and not to be trusted with smaller snails, but pointedly because the crabs wanted the shell.
<Mmm, no, not just the shells... but for food as well>
Your website definitely mentioned that one should stay away from housing hermits together with any similar sized snails, with attractively shaped shells, but that if kept well fed and given extra shells the crabs probably would not bother snails, especially those much bigger or smaller than themselves.
<Size bears little relation to predation here... the Hermits will eat the largest of Gastropods if hungry>
I want to keep the abalone, but would rather not keep them as the only thing in the tank, I really want some crabs or shrimp for interest. Would another
type of sand-sifter/algae eater be a less predatory tank mate for the abalone?
<Mmm, yes... but really better to counter algae here in other ways.
Competition, nutrient limitation, removal...>
Do the abalone have the possibility of growing to near-full-size?
<If conditions are propitious, yes>
I read elsewhere that they are very sensitive to changes in salinity, and usually don't last long in captivity. But if they would continue to grow, and the hermits are a real threat, I will gladly take back the hermits to keep the abalone. Please let me know what you think, and thank you SO much for the great resources and info you provide!
Katie P.
P.S. you can, of course, edit this email to a reasonable length if you wish to post it!
<No worries. Katie, if you're very interested in these snails, I would return the Hermits. Cheers, Bob Fenner>

Will hermit crabs attack anemone? 03/11/09
i have a pink tip Haitian anemone, and i looked at my tank and saw that it was smaller than normal. it almost looked deflated. i then saw a small hermit crab clawing at the anemone. this didn't look normal. should i take one or the other out of the tank? i have a few hermit crabs.
<... I would remove one or the other... Robert... please don't send out such poor English... at least to us. Bob Fenner>

Blue Legged Hermit Crab/Compatibility 3/4/09 As always, thanks for the wonderful site! <You're welcome.> I have a quick question. Can blue legged hermit crabs ever pose a danger to SPS corals? <No, is one of the few "reef safe" hermit crabs and feeds primarily on algae.> Thanks, <You're welcome. James (Salty Dog)> Jan <<RMF would NOT say that any Hermit would never pose such a danger... even just walking on corals can be harmful>>
Blue Legged Hermit Crab/Compatibility 3/4/09
Bob, In regards to <<RMF would NOT say that any Hermit would never pose such a danger... even just walking on corals can be harmful>> Mmm, we need to change the picture caption on Hermit Crabs. I have checked here for any possible problems with this crab and I read; "Clibanarius tricolor, the Blue-Legged Hermit Crab. To less than an inch in length. One of a few "reef-safe" Hermits that stay small and almost exclusively feed on algae (and Cyanobacteria!). Good for aiding in aerating the substrate as well. Aquarium photo." James <What's that saying James? "Never say never". See above... "... almost exclusively..." B>
Re: Blue Legged Hermit Crab/Compatibility 3/4/09
Ahh, so right. James <I do hope you like to drink biers... at the upcoming conf.! B>

Re: Final Stocking Order 1/5/09 As I think about how to implement your recommendations, I have a few follow-up questions... I'm thinking about downsizing my B/F, angel, tang and Anthias selections to make room for more Anthias and Chromis fishes, as you suggest. Here's what I'm thinking: B/Fs: 1 Latticed, 1 Pakistan, 1 Pearlscale and 1 Bluestriped Dwarf angels: 1 Bicolor, 1 Flame and 1 Coral Beauty. Will 3 dwarfs likely get along in a 220g if added at the same time? <Likely so> Tangs: 1 Kole and 1 Tomini. The Kole article on WWM suggests that 2 Kole Tangs would likely get along in this size tank, but I'd prefer a little diversity. Would the Kole and Tomini likely get along? <Ditto> Anthias: 4 Bartlett's (the male and female I have now, plus 2 more female) and 3 flame Anthias. Should I add the 2 Bartlett's and 3 flame at the same time, or should I complete the Bartlett's group before introducing the Flame group? <Six of one...> Generally, I also realize that the B/Fs, angels and tangs are all similarly sized/shaped. Should I be concerned, or is this enough diversity for this sized tank? <... Is, IMO> One last unrelated question... IPSF.com lists micro hermits as no threat to the snails, but I'm having my suspicions after seeing one trying to pry open one of my sandbed clams. <I'd believe my own first-hand experiences... "We're bringing freedom to Iraq"... No, we invaded a sovereign nation and have murdered hundreds of thousands of their citizens> Seems to me they may still decide that they would prefer one of my snail's shells more than its own <Mmm, with all Hermits, one needs to be providing a mix of shells for "upgrading"... otherwise they will improvise> or may just want to take one apart for the fun of it. Are micro hermits really safer, or should I be almost as concerned about them as for the bigger hermits? <Less concerned, but still so> With two Bristletooth tangs and the rest of my clean-up crew, I'm thinking about evicting the micro-hermits. <I would as well> Thanks again! <Welcome! BobF>
Re: Final Stocking Order 1/5/09
You are too funny... I think I'm finally set on my final selections and stocking order. Thank you for all the valuable insight to help me nail all this down. Cheers! Sean <Happy to conspire with you Sean... Anticipation is a huge part of fun in this hobby... even more so when shared with others who are intelligent, sensitive and open to possibilities. BobF> I agree completely!

My Hermit Crab is killing my other invertebrates. -12/11/08 Hi...I just bought another electric orange hermit crab and within hours of putting him in he killed another electric orange hermit crab. Then next morning my blood shrimp is found dead and the hermit was eating him. Now its been three days and I just found him eating my pom pom crab. When I saw him at the store he was trying to get at a smaller hermit crab. Should I have known then that he was too aggressive? Is it common for hermits to kill other inverts to eat? <Mmm, some species much more than others... but yes. See here: http://wetwebmedia.com/hermitcompfaqs.htm and the linked files above> Could there be any other reasons for this problem? I have a 12 gallon Nano and all my water parameters are great. I change my water every other Sunday and I buy the water at the store where I get my stock. I have a splendid Dottyback, a yellow headed Goby, candy cane pistol shrimp, two ocellaris clownfish. <... this is too much fish life for this small volume> I have two small electric blue hermits, a small zebra hermit and a scarlet hermit. I also have about 8 different corals. <...> I had a Blood shrimp since I set up the tank two months ago. I had a pom pom crab that seemed to be doing great. Both had molted before and the pom pom was just finally starting to get comfortable enough to come out more. I also had a another electric orange hermit, but as I mentioned above this new hermit has eaten all three of these inverts. Please help!!! <... please read the compatibility file FAQs on WWM for all you have, list, and want to get in the future. Bob Fenner>

Tiger Tail Cucumber, comp. 09/27/2008 Crew, <<Zach>> ?I have been reading on your site, and it seems that the conclusion is that a Tiger Tail cucumber is capable of wiping out a system if it eviscerates, but the chances of this happening in a stable system is slim. I have a 75 gallon reef with 10 scarlet reef hermits, and after reading Marine Invertebrates by Ronald Shimek he states that hermit crabs can bother cucumbers. Is this true. It seems that my scarlets are very peaceful, and go about there business picking at algae and even climb over each other without fighting or bothering anyone. They have plenty of shells to upgrade into as well. <<Yes, i would agree with Ron, this is certainly very possible. Up to yourself is you feel its a viable risk to take>> Zach <<Hope this helps. A Nixon>>

Nassarius Snails Eating Hermit Crabs - 6/21/08 Hey WWM Crew, <Hi Brian! Lynn here today.> Love the site and thanks for taking the time to sift through everyone's questions. <It's a pleasure.> I have something going on in my clean-up crew in my saltwater tank I haven't been able to find out anything online about. <Let's see what we can do to fix that.> I have a 75g tank about 2 months old now with just live rock. The ammonia and nitrite levels were at zero after a month when I added 10 small blue leg hermit crabs, two Emerald crabs and five Nassarius snails. I have read all over about hermits taking out your snail population <Yes, it can certainly happen. Many, including myself, avoid keeping hermits in reef systems altogether.> ..but in my tank it seems my snails are taking out my hermit population. <Uh oh> I have witnessed on three occasions the snails harassing the crabs. <Calling them names? Telling them bad hermit crab jokes like: How much does a hermit crab eat? Just a pinch! What's a hermit crab's favorite dessert? Clawberry Cheesecake! I guess I can see where that would be annoying.> The first time the hermit left its shell and headed to the rocks and returned later to collect its home. <Awww, poor little guy.> Then about a week or so ago I saw a snail envelop the crab with about five or six hermits in a conga line on the shell of the crab getting eaten (maybe trying to pull him back?). <It sounds like the crab was already dead or in a significantly weakened state and it attracted every scavenger in the area.> Another snail crept up from the sand bed to help and eventually the crab was eaten. <That sounds about typical, again, if the crab was dead or dying.> Just now I peeked in my tank to see another empty shell and two snails leaving the scene of the crime. <Not good.> Have you ever seen or heard about this before? <I've never heard of the common Nassarius vibex snails attacking and killing healthy hermits, no. What I'd do first is make sure that the snails you have are indeed N. vibex. Please see this link for comparison: http://www.gastropods.com/0/Shell_1930.html . If you have something else, let me know and we'll see if we can't figure out what it is. Otherwise, I have a feeling that with such a new system, the problem might be one of too many scavengers and not enough food to go around. Keeping everyone well fed will go a long way to ensuring healthy individuals and keeping the peace. Also, it goes without saying that keeping the water parameters stable and in good shape is a must.> Am I missing something as a food source for these snails that is leading to this behavior? <Just make sure that they're all getting enough to eat - any meaty foods of marine origin, sinking pellets, etc.> Any thoughts would be appreciated. <Let me know if you have a different species of snail, or if things don't improve!> Thanks! Brian <You're very welcome! Take care, -Lynn>

No more hermits and skip the crab too! 5/23/08 Hi Crew, <Hi Sam, Lynn here today.> I have a 10 gallon for over 5 years now. Over time I have had different kinds of snails and sometimes hermit crabs. I have pretty much given up on the hermits because even the best of them will kill snails to get the shells. <Yes, hermits can be destructive little creatures, particularly in small systems.> I can't say I actually saw them do it but every time I decide to try hermits my snails all of a sudden start to disappear. <Yep, there you go.> But my grandchildren do like to see them scurrying around, so every once in a while I try the Blue legs but always the same results. <LOL So the lesson is...! Unfortunately, Blue leg hermits (Clibanarius tricolor) are quite the little pickers/scavengers and not to be trusted around other snails/small critters.> Anyway, I was wondering if I could try an Emerald crab. They are supposed to be herbivores (same with blue legs). I do have a clown goby in the tank. Any danger here or are all crabs crabby? <I wouldn't take the chance as these crabs can be problematic as well. How about a nice little Scarlet/Skunk cleaner shrimp (Lysmata amboinensis or Lysmata grabhami) instead? These pretty little shrimps are hardy, reef-safe, and fun to watch. Please see this link for more info/photos: http://www.wetwebmedia.com/hippolytidae.htm > Thanks Sam <You're very welcome! Take care, -Lynn>

Suspicions regarding hermits..! 05/15/08 Hi everybody :) <Carolyn> Over the past few months I've noticed that the polyps on my Montipora digita frags were disappearing, and the white coral skeleton is now visible. After spotting two Asterina stars on the rock close to the frags and knowing they can be a bit of a pest for sps munching I quickly removed and sumped them, thinking that would be the end of the matter. Weeks later however yet more polyps have been removed and there are no signs that any more Asterinas are in the tank (much sitting up at night starting into the moonlit tank...), so I'm beginning to suspect another culprit - we have two blue knuckled hermits (blue and yellow striped legs, orange antennae), which were originally sold as reef safe blue legged hermits, and I'm wondering if they may be to blame? <Quite possibly> The other inhabitants are a (now very plump and content) mandarin, coral beauty and a Randall's shrimp goby. Looking forward to benefitting again from your advice :) Carolyn <I'd remove these to the sump as well. Bob Fenner>

Thinstripe Hermit Crab (Eating Everything!) - 05/09/08 Hi there, <<Hello>> Firstly I must say I use your site regularly (it's great) and usually find an answer to any questions I have, however, on this occasion I have come unstuck! <<Oh?>> I currently have a Red Sea Max 34g tank with full reef setup. At the beginning I was duped into believing that a Thinstripe hermit crab would be a suitable reef tank-mate. <<Hmm…I honestly don't consider "any" hermit crab to be reef-safe…and many species can be downright destructive>> The conditions in the tank a perfect and as a result the hermit has grown very well, a little too well and is getting quite big, at least a couple of inches. <<This is a problem, in my opinion>> He is very boisterous, knocking over corals and others things plus he likes to rearrange the tank now and then. <<Another negative aspect…aside from their opportunistic feeding habits>> This behavior clearly upsets my corals especially the Goniopora, Pulsing Xenia and polyps. Lately he has been getting onto the Sarcophyton sp (about 5-6inches wide) and eating its' tentacle thingies (not sure of the technical term!) <<Polyps>> At which point it closes up and recently started eating the tubes of the fan worms, nipping at the finger sponge and I saw an end of the pulsing xenia floating about as well (maybe he had a go at that?). <<Best to remove this very predaceous hermit>> You don't think it is a food source problem, he is just very opportunistic! <<Indeed>> Clearly I need to remove him from the tank and I am sure the LFS will put him in one of their big display tanks, however this guy (his name is Rocky!) is so cool, he is so much fun to watch so would be reluctant to get rid of him. <<Interesting creatures for sure>> My question is this, is it possible to put him in a separate smaller tank on his own without the need to have all the equipment? (Skimmer, powerheads, lighting etc) I known the Thinstripe hermit is very hardy and can go for long periods out of water so could I get away with a small amount of live rock, standard tropical lighting, standard heater, a simple filter and regular water changes (maybe a small powerhead but I don't think this is necessary)? <<This could work, yes…be careful not to over feed, and make sure you monitor Nitrates and keep them down with the regular water changes…and do also supply some water movement via the powerhead>> Any help much appreciated. Colin, London <<Happy to assist. EricR, South Carolina>>

Dardanus venosus in my tank!??! Maybe - 5/2/08 Dear WetWebMedia crew, Hello again. <Hello Sherry> I'm not sure how this hermit got in my tank, but is it Dardanus venosus, the Starry-eyed Hermit Crab, which grows 3-5 inches? <I'm sorry, but I can't see the details well enough to make that determination. Did it hitchhike in on rock from Florida, the Bahamas, or the Caribbean?> It has blue eyes, <Do these have the distinctive star patterned (pseudo-)pupils?> ..lavender claws and it is bristly. Currently it is about 1" from claw to claw, or leg to leg, however you measure. If it is a starry-eyed hermit, how long may I expect it to stay small and relatively harmless? <Growth rate will depend on water parameters and how well it's fed. How harmless it is, depends on what you have/value within your system. It's also related to the relative size, speed, and accessibility of its potential prey items. If you have a tank loaded with very small fish and snails it could already be of a threatening size. If, however, it's in a tank with very large fish, it wouldn't be too much of an issue. If it is indeed Dardanus venosus, it should only be in large, fish-only systems.> My son saw it pinch a Zoanthid polyp, but besides that it is a good scavenger. <I bet it is!> Best regards,
<Take care, -Lynn>

Re: Dardanus venosus in my tank!??! Maybe - 5/2/08 Hello, <Hi Sherry> I just wrote to you about this crab, and then he was nice enough to walk across the sand so I could take a couple of more pictures. These are my three best pictures of him. It's hard to get a good picture, but I think you can see the leg colors, blue eyes, etc... Any idea what it is? <Unfortunately, there are many possibilities. Without being able to see more detail or know where it came from, I really couldn't tell you with any certainty. My best recommendation is to look through the photos at the links below for comparison. I'd also recommend that you keep a sharp eye on the little fellow if you decide to keep it. The important thing about hermits is that even those that are generally considered harmless have the potential to prey on/pick at some of the favorable biodiversity within a system, including snails. They're also quite bold when it comes to removing/robbing food from corals - sometimes to the point of the coral's decline. Hermits are neat, but opportunistic little creatures whose threat potential increases with size, crowding, and lack of sufficient food. Keeping them well fed can help deter predation to some degree, but the potential risk is still there. Here are the links I mentioned earlier: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm This link is in French, but it has some excellent photos with species names included. http://www.recif.be/article/hermit.htm > -Sherry <Take care, -Lynn>

Elegant Hermit Crab, coral abrasion 4/19/08 Hello Guys, <Scott> I just bought a beautiful hermit crab which I believe to be Aniculus elegans, the elegant hermit crab. This ID is based solely on looking at photos on the web and noting that most, but not all, of the sites identify him thusly. A few think he is a Hairy Hermit Crab, Dardanus Sp., including my LFS where I bought it, That Fish Place. The crab's colors match EXACTLY the pink and maroon coralline algae on its shell, and the tips of his hairs are turquoise. The crab is very beefy, i.e., all the outside legs are thick and strong looking, which doesn't come through at all on any photo I have seen. My questions: 1. Is he Aniculus elegans; or can you point me to some web resource that will help me identify him - that does not appear when you google "Aniculus elegans" OR ("A. elegans" AND Aniculus)? <I do think this ID is correct> 2. How often should I give him some fish or chicken? <No chicken... too fatty, hard to digest...> I am concerned that he is not getting enough food (due to his exoskeleton, I cannot see if he is skinny). He is rather lethargic compared to all my other hermit crabs (three thin striped plus lots of reef janitors). He grabs and eats VERY sloppily the fish and chicken I give him, but I would expect him to be scouring my rocks looking for coral. <I would offer this animal aquatic-based proteinaceous food purposely 2-3 times a week. Maybe via tongs...> From the book, *Life and Death of Coral Reefs* Edited by Charles Birkeland, chapter 4, *Bioerosion and Coral-Reef Growth: A Dynamic Balance*, by Peter W. Glynn, Page 79: Two species of hermit crabs that feed on live coral produce large amounts of calcareous sediment when they scrape corals to remove soft tissues (Fig. 4-1). The average mass of coral abraded by a small hermit crab (*Trizopagurus magnificus* [Bouvier]) was about 10 mg ind.?? day??, and for a large hermit crab (*Aniculus elegans* Stimpson) about 1 g ind.?? day?? (Glynn et al., 1972). Relating hermit crab population densities and erosion rates, it was found that *Trizopagurus* and *Aniculus* respectively were responsible for the generation of about 1 and 0.1 metric tons of coral sediment per hectare per year on a fringing reef in Panama (Table 4-2). Since this rate of coral abrasion by hermit crabs has not been reported elsewhere, it is possible that these high levels of erosion are unique to the eastern Pacific. <Wow!> Grace and Peace, Scott <I would keep an eye on this (and all other hermits, true crabs...) vis a vis your stony corals. Cheers, Bob Fenner>

Re: Coral eater, hermit crabs... 2/5/08 If that's the case, how do I identify which crabs are coral eaters? Just by watching them or is there some other way to find that out? Thanks again, Kash <Observation or reading... RMF>

Red Legged Hermit Crab/Compatibility 11/09/07 Hi, <Hello mystery writer> I was wondering if you ever heard of red legged hermits eating Turbo Snails? I've had my tank running for about a year and have had no major problems. All of a sudden in the last 2-3 weeks I've lost about 5 snails. So I purchased a few more 3 days ago, and looked in today to find a red leg eating one. <If your Red Legged Hermit Crabs are the Calcinus sp., all should be fine. If Dardanus or Ciliopagarus, no, they are known to attack and eat snails. All hermit crabs will eat dead animal tissue and it's possible that the snail was already dead when you observed the crab eating it. Read here and linked files above. http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm> Also I have a green hair algae growing out of control any suggestions other than chemical? <Read here and linked files above. http://www.wetwebmedia.com/algaeconMar.htm James (Salty Dog)> Cal. 440 Mag. 1076 Alk. 11.6 Amm. 0 Nitrites 0 Nitrates 5

Hi everyone, I have a question about hermit crabs and refugiums 10/20/07 Hi Everyone, <Ed> You've all been a great help in resources on the web! I have a 20L with a 10 gallon refugium. The refugium is lit with two daylight 100w bulbs as well as 18w actinic and 18w 10,000k PCs. Currently, I have an arrow crab, <Keep your eye on this... become predaceous> 4 blue hermit crabs, as well as Chaetomorpha, and Phaeophyta (brown macroalgae). My question is, will the crabs (arrow and blue) be detrimental to my refugium? <Mmm, yes, in terms of eating organisms that should not be...> I ask this because I have recently decided that I would like to use the refugium to culture amphipods and copepods that are already growing within the tank. Will they pick them all out to extinction? <Too likely yes> Also, as a side question, what are your thoughts for Phaeophyta as a macroalgae for refugiums? <Can work... some species and types of systems better than others. Many colder water rigs especially. Need to pay attention to regular iodine/ate supplementation> Are they as bad as or better than Caulerpa? <Mmm, no> I know that the site does not recommend Caulerpa in the refugium, but could not find any info about Phaeophyta. <Is a huge group/Division of mainly macro-algae... Not well investigated for ornamental use as yet> Actually, I have another question. Too bad you all don't get paid for the number of questions we aquarists love to ask. <Would be a different venue if so... Not of my desire, design> I do have corals in the main take. I would like to know if it is possible to use the refugium to grow up zooplankton or phytoplankton? Is this possible and is it difficult? <Can be... not difficult; though more specialized gear would be better... particularly for the phytoplankton. You might benefit from searching out, reading Frank Hoff's work> Thanks Ed <Welcome. Bob Fenner>

Anemone Ate Hermit Crab - 7/18/07 Hi!, <Hi Sol!> Today I bought some tiny hermit crabs, no more than 1cm across. When I put them in they started to walk around the tank. Before long one of them had found <it's way(?)> in into the tentacles of my anemone (Heteractis magnifica). It has now completely consumed the hermit crab into its mouth (about 4cm across). Is the anemone going to be ok? <Should be fine. The anemone will regurgitate the shell/what it can't consume.)> I'm not so worried about the hermit crab, but I don't want it to start eating from the inside out. Can you please offer your advice. <See above.> Thanks a lot in advance. <You're very welcome! -Lynn> Regards, Sol Jennings

Snail murder, SW Hermit comp. 3/23/07 Hello! I have another question for you guys. I have a new 20 gallon tank with just 10 snails and 4 hermit crabs. Recently, I was watching my tank and I noticed something very strange. My hermit crab had basically killed my snail and it was eating the snail out of its shell. <Not strange at all actually> I was wondering if you could tell me whether or not this is normal behaviour, and if I should remove the empty shell from my tank. Thank you! <Is normal... or at least not atypical. These "false crabs" as a general group (some are more herbivorous) are opportunistic omnivores. I would leave the shell put... may become another Hermit home. Bob Fenner>

Overstocking, Hermit Crab eating snails - 2/26/07 <Hi Tracy, Brenda Here tonight.> Thank you for your great articles. <Your welcome.> We have a 33 gallon tank that is about 1yr running now. We started with live sand and began adding live rock and snails 1 month later. After 6 months we were up to 70 lbs live rock, 3 turbo snails 15 blue leg hermits <You have too many crabs. I recommend one per 10 gallon or less.> 6 Margarite snails, 1 sally light foot 1 cleaner shrimp, lots of little feather dusters on live rock, I have seen some bristle worms too, 1 blenny, 2 tiny maroon clowns and a yellow tang, 1 very small anemone its white and about 1/4 of an inch big. <1/4" anemone? Pest anemone? Your tank is much too small for a tang.> There is coralline growing and we have star polyps. All was well for a few months then the tang died. We checked the water (prior to this we change 10% every 2 wks) and did a 50% change the ph was 8.2 and nitrate 10 Two days later we did another water change. The salinity is kept at 1.023. The place where we get our supplies checks the other levels for us and said they were good. <Nitrates at 10 is not good, need to be zero. I suggest purchasing your own test kits and learning to test all of your water parameters. What will you do at midnight when you need to know your water parameters?> After the tang died the tank became over run with red slime algae and green hair algae. <Have you checked for phosphates?> We were able to combat the red algae but the green was unreal. We had to remove the fish to a holding tank and clean the algae of the live rock you couldn't see any live rock the algae was so bad. We scrubbed off the algae under RO water. Everything seemed nice and clean we tested the water, the store said all looked good the nitrate still at 10 though. <The LFS is not doing you any favors by telling you that your water is good when nitrates are above zero.> We put the fish back in and purchased a zebra turbo snail and 5 Nassarius snails and a conch snail and a peppermint cleaner shrimp. That was about 1 month ago 1 week ago we got a pink tipped anemone for the clowns who have out grown the little tiny one (sorry don't know what kind it is) the pink tipped hasn't quite settled yet still on the move some how I think it is running away from the clown that wont leave it for a second it actually lies down on its side wrapped in the tentacles of the anemone. <Buying any tank mate and not knowing the species is a bad idea. Your salinity is too low for an anemone. It should be 1.026. You have two anemones, and I have no idea what kind. You won't be able to successfully keep two species of anemones in a 33 gallon tank. A 33 gallon tank is border line for even one anemone, unless you are experienced with keeping anemones. Your tank is overstocked, and I believe you will continue to have problems. The anemone has not settled because it is unhappy with its environment.> Now 3 snails are dead, one of the hermit crabs is now very huge could he be eating them? <You bet it can!> He moved into a very large shell and looks to be about 2 1/2 inch by 1 inch big. Do you think the anemone has something to do with it? <Nope!> Thank you Tracy <You're Welcome. Please research all of your livestock and learn their requirements and compatibility with others before you buy. Good luck with your tank. Brenda>

Red Serpent <Brittle> Star Compatibility with Orange Legged <Not Reef Safe> Hermit Crab 1/29/07 Hi guys and gals, <Hello Gordon, thanks for the inclusion! Mich with you this evening.> I bought a perfect looking red serpent star yesterday (about 6 inch diameter) from the LFS. <I presume you mean a Red Brittle Star (Ophioderma squamosissimum).> I acclimatized it over a few hours and then released it into my 55 gallon (fish and live rock with a couple of mushrooms and feather dusters and many invertebrates -- cleaner shrimp, peppermint shrimp, banded coral shrimp, Nassarius/turbo/Trochus/zebra snails, a number of very small (3/8 inch) orangey stars, and a variety of hermit crabs). Almost immediately after the red serpent star was released into the tank, the largest of the hermit crabs (an orange legged fellow about the size of a ping pong ball or golf ball) made a beeline for the star and pounced on him, apparently trying to rip chunks off the poor star. <Yikes! That is a very big and most likely not reef safe hermit you have there!> I'm not sure, but I think perhaps the star exuded some kind of chemical defense, because the crab ended up with a gooey substance adhered to most of his legs and claws. I watched the duel for about a minute, to see if perhaps the crab would beat a retreat. The star had wrapped his legs all around the crab and his adopted shell, apparently in an effort to fend the crab off. Not wanting any further harm to come to my new friend the serpent star, I separated the two combatants and sequestered the crab to a jail cell. The LFS of course had assured me that there would be no compatibility issues. <Most likely assumed the hermits you had were of a reef safe variety.> I have Googled the topic and searched WWM for similar queries for the past couple of hours but haven't found any definitive answers. I guess my question is -- Can this crab and this star live together peacefully or will the crab continue to harass and pick on star until he eventually (or quickly!) succumbs? <Hmm, when I initially read this I missed the size of the hermit crab, this is a big crab and I suspect that it is not reef safe. Most larger hermit crabs will prey on smaller, and sometimes larger animals. I do not think your other tank residents are safe in the presence of this hermit. Do you have a refugium where he might reside? I think it may be time to find your hermit a new home.> And will my other tank inhabitants (community fish, a goby and the invertebrates mentioned above) be safe and compatible with the serpent star? <Should be with the star, but I question the safety of all with this hermit.> Any advice would be much appreciated! Thank you for your response. <Welcome! -Mich> Gordon
Re: Red Serpent <Brittle> Star Compatibility with Orange Legged <Not Reef Safe> Hermit Crab 1/29/07
Hi Mich, <Hello again Gordon!> Thank you for your reply. <Welcome!> I think you meant "Ophioderma squamosissimus" and yes, I that certainly looks like the same creature I have bought. <Yes, sorry lost a letter along the way while cutting, pasting, spell checking and such. Glad you were able to figure it out.> When I said the orange legged hermit crab was the size of a ping pong ball, I meant that his adopted snail shell is about that size. <Yes, I understand, but still unlikely to be a reef safe variety. The size and the orange legs make me think he may be something along the lines of an Anemone hermit crab (Dardanus pedunculatus) or a small Giant hermit crab (Petrochirus diogenes).> He's a pretty good sized hermit crab, but his own body of course is much smaller than his shell would suggest. Up to now, this crab hasn't bothered any of the other tank inhabitants, as far as I know. But I guess you're right, it's hard to predict for sure but the larger the crab gets I suppose the greater the risk that he'll attack and eat something. <Yes.> I was hoping that someone with more experience than I would reassure me that after this initial altercation, the two would soon grow accustomed to each other and leave each other alone. <It is a possibility, but I would not trust this crab.> I'd hate to get rid of the crab unnecessarily. <I understand.> He's an active and colorful addition to the tank. <As long as he's not also subtraction other additions!> I had a similar dynamic with a 5-6" Humu Humu and a very large red-legged hermit crab who had a rather violent fight when they first met (when the crab was added to the tank) and then left each other alone thereafter. <Again, is a possibility, but I would not assume all will be alright.> By the way, do you know if this Ophioderma squamosissimus is capable of producing a slimy defensive substance that might have gotten all over the hermit crab when they first tussled? It was kind of white and fluffy looking. <Ophiuroids are microphagous ciliary mucoid feeders. They can exude mucus to trap food, usually plankton. This may be what you observed.> Thanks again. What a great resource your site is!!! <Welcome! Glad you find the site beneficial. -Mich> Gordon
Re: Red serpent star compatibility with orange legged hermit crab 1/29/07
Hello Mich, <Hello again Gordon!> I believe the crab in question is actually a "Calcinus Sp.", at least according to the source from which I bought it. (Not sure what the "Sp. is short for.) <Refers general to any species.> This is the description that the vendor provided. http://www.etropicals.com/product/prod_Display.cfm?siteid=43&pCatId=2251 <OK.> Here's a picture: <OK.> I bought several of them a year or so ago and this particular individual has definitely grown much larger than any of his brethren acquired at the same time. Perhaps he is a "giant among crabs". <A possibility.> Well thanks again for your advice. <You're welcome. -Mich> Gordon

Hair algae, P. diadema, and Zoanthid rejuv. 1/25/06 Hello folks, <Deb, glad you could join us.> Thanks so much for all of the helpful information. <We *try* to be helpful!> In the next 6 months, I'm going to be upgrading this tank to between a 150g and 250g system. At that point, I will make my 55g into the sump for the main tank. I will either section part of this off for a refugium, or I've got a 20g that I can hook into the system as a refugium. When I do this, my canister filter will go away, and I will be implementing a DSB in the main tank. Until I can do this, I plan to continue weekly 20% changes (replacing one section canister filter media each time), continue aggressive skimming with the CPR BakPak, and continue to ensure that the current in the tank is strong. <Very glad to hear that you are moving beyond canister-filtration. You will be moving into a much more versatile/useful configuration.> At this point, my Cyano problem has seemed to cure itself. In doing the weekly water changes, I found that the pump servicing my SQWD system was clogged. This was inhibiting water flow significantly in the tank. Now that I serviced it, there's a pretty strong current in the tank, which probably helped to eradicate the Cyano growing in the tank. <Most likely, this helped a lot!> Also -- my Halimeda is making a comeback, though I still need to continue cleaning hair algae off of it every couple of days. The bubble algae is still present in the tank, but somewhat manageable, as I can gently pull it out during water changes and dispose of it. <Are you sure you have bubble-algae? Sometimes, I think folks think BGA is bubble when it has gaseous packets in it's layers...> So, the only real problem in the tank is the hair algae. It's still growing quite rapidly. In trying to fix this problem, my bicolor blenny stopped eating and has "disappeared" in the tank. <Maybe he needed a vacation. Heck, if I had to eat hair algae...> I'd like to pickup a lawnmower blenny to replace him and to help with the hair algae problem. <Remember, Deb: This is dealing with the symptoms of a water-quality issue. IIRC, your last phosphate test was .03ppm, and I was asking how sure you were of the accuracy of that result. Where do you stand now? Did you ever buy a new kit?> Once the hair algae is gone, I plan to supplement his feeding with various algae foods (as I already do for my Coral Beauty). <Should pose little problem with a little research...> Adding him will result in having the following fish in the tank: 1 coral beauty, 1 Dottyback (Pseudochromis diadema), 1 yellow-tail blue damsel and 1 lawnmower blenny. Does this seem like a sound decision to add this fish? <As long as you aren't hoping for a total massacre on the hair algae, yes. In my experience, algae-eaters always choose to ignore the one thing you bought them to eradicate.> Otherwise, my zoanthids have stabilized a bit. They're not dying off anymore, but they're not flourishing as they've been for the past few years. Only a handful are opening up, and not fully at that. <All this points to a water chem. issue to me.> I'm hoping that they are on the road to recovery. I'm supplementing the daily feedings now with Cyclop-Eeze, in hopes that the added nutrients will encourage their growth. I also use a plastic turkey baster to blow water over them with each water change to try to free them of the hair algae that grows around them. I've ordered new test kits for my phosphates, silicates and nitrates, and they should be arriving any day now. <Ahh, very good. A reputable, reliable manufacturer, I hope. Mmm, one note: Silicates aren't a factor unless you have huge diatom blooms, so worrying about the concentrations is moot IMO. I don't own a silica test kit.> I've taken the water changes down to 1x per week, 20% using RO/DI water. I've just gotten new cartridges in for the RO/DI unit and will be replacing them this week. I've also cut back my lighting schedule, taking 1.5 hours off the back end for both the daylight and actinic lighting. <Good steps, all.> In doing all of this work, I've realized that I haven't replenished my cleanup crew in years. I've still got about 10-15 Astrea and turbo snails in the tank, but all of the small crustaceans are gone. I'd like to replenish this crew, but am afraid that any crustaceans I add will be decimated by my Pseudochromis diadema. Any ideas on what types of inverts I can get to replenish this crew that will survive the presence of the Pseudochromis diadema? Having a well stocked cleanup crew may also help with the algae problems in the tank. <Hmm... I never worried about a P. diadema bothering hermits to the point of murder. Types and compatibility of hermits is not a strong-suit of mine, but I know we have the info here on WWM if you look for it.> So, to summarize: -Lawnmower blenny for this tank -- good or bad idea? <Good, in your case.> -Any ideas on how I can nurse my zoanthids back to health? <Provide optimum water conditions: temp, movement, quality, feeding, lighting spectrum/duration.> -Any ideas on how I can supplement my cleanup crew without buying an expensive smorgasbord for my Pseudochromis diadema? <Mmm... *I* don't see a problem with the "generic" red-legged hermits here. (RMF strike me down if I am in error)> Thank you so much for all of your help. <Oh, Deb. You know we love you. -GrahamT> Deb

Scarlet hermit crabs ganged up on Mandarin? 1/19/07 Hi, <Hi> I have a quick question about scarlet hermit crabs. I know they are good to have in a reef and they are supposed to be less aggressive then other hermit crabs. I saw to my dismay this morning four of my large scarlet hermits tearing apart my small twin spot mandarin!!! The mandarin has been in my tank for about a year or more and was doing very well. I hadn't seen any sign of him being sick. Could the Scarlets have grabbed a hold of him while he was resting at night or would it be more likely that for some unknown reason he died and the Scarlets were just doing there job? <The latter is much more likely unless they are very large. They do not work together to bring down larger prey which would be necessary in this case.> At this point in time I'm inclined to take all of my larger Scarlets out and trade them in for smaller ones. I've had a few small fish die here recently and I'm not sure if it's because of the some tank condition or if these Scarlets are just more aggressive when they get big. <Would look for other causes here.> Craig <Chris>

Doing What Come Naturally….Lion Eating Hermits 1/16/07 I have a really big problem, <I'm all ears……> in my tank of about 450 litres, I have a Pterois volitans that have eat an hermit crab. <Sounds like natural behavior for the lion…….> I am very worried , he seams to be ok (to days later) The hermits are from Brazil, very small ones, I have more or less 20 hermits crabs in my tank and about 20 snails too. Can my scorpion digest it? <If he was large enough to swallow it whole, he should be able to digest it just fine. In fact he will continue to eat the rest of the hermits and snails.> will he die for eating it? <Not likely.> Please tell me what do you think it will happen. <I think your lion will continue to practice this natural behavior on smaller tank denizens.> The Pterois is about 15 centimeters long and 43 years of age. <I'm guessing that age is a typo or was lost in translation somewhere……….> Thank you very much from ARGENTINA (SOUTH AMERICA) ALEJANDRO <Adam J. from SoCal.>

Hermits safe with Live Rock? 10/24/06 Just a quick question, I found only bits and pieces of this topic answered throughout the site... I have 50 lbs Fiji LR from Drs. Foster and Smith (really nice stuff by the way, minimal die-off after a good scrubbing) This was added to a tank that already had 7 blue-legged hermits in it. I'm a bit concerned because the crabs seem to just graze off the rock, picking everything out of the tiniest nooks and crannies. Should I be concerned about the crabs overgrazing the LR? Thanks Again! Bryan <This should be fine, the hermits should not be able to significantly effect the amount of life on this amount of LR.> <<RMF disagrees... a matter of how much life, how much LR, how many and size, species of Hermits... can/do denude at times.>> <Chris>

Puddingwife Wrasse...Snail/crab compatibility 9-19-06 What up WWM Crew? < A preposition for a direction. Just kidding, howdy! > I've put a deposit down on a juvenile Puddingwife Wrasse so that I could do some more research on them...he was cool looking/interesting in the store. < Beautiful fish. Research ids always good, I could use some myself! > I've found that he will one day be too big for my aquarium, but am willing to deal with that problem when it arrives. < Spoken like a good foster parent. > I've read that they eat mollusks/sea urchins in the wild...that being kind of a broad statement, do you think that my snails and hermit crabs will be in danger from this guy? < Oh, yes. One of their favorite things to do is to pick up the snails/hermit crabs, and beat them on the rocks until the good stuff comes out. Horribly entertaining, but very taxing on your clean-up crew. > Also, are these fish generally wild caught or farm raised? Just curious. < Wild caught, but captive breeding is being worked on daily. > Thanks again, Brad < Good luck! RichardB >

Hermit Crab Predation - 09/09/06 Hi all and many thanks for the fantastic site. <<Welcome>> I've been trawling for info on whether my Blue-legged hermit crab can survive what I think is an onslaught from my Red-legged. <<Mmm...not likely>> I came home this evening to see one of the heads of my branching hammer not a happy bunny. As usual, they are quite a good indicator of problems, this time an ammonia spike. <<Indeed....and kudos to you for the astute observation>> Looking for the source, I found my small (half the size of the Red-legged hermit) Blue-legged hermit crab laying on a rock with a piece of him separate. <<Unless your tank is VERY small with inadequate bio-filtration, I doubt this to be the source of your ammonia spike>> He has lost 4 legs and a section of flesh. <<The red-legged hermit was probably trying to eat the smaller crab>> The legs are about 6mm long and very thin. The flesh by the time I got to it was white but mostly interior Chiton from what I can feel and had the indications of a tiny red dot in the separated surface. This is about a third of the length of the legs. I was about to remove the shell but saw movement and have laid him on a rock to see if he recovers. Is this likely? <<Highly doubtful...and the red-leg will be back for more...>> I was going to put the Blue-legged crab in the sump on a temporary basis (or maybe that should be the red-legged) to stop harassment for the duration of the move. <<Likely a moot point by now>> The Red-legged is looking for a new home I think. <<Always , yes>> He's turning over the spare shells and moving around the tank at a rate of knots. The shell he was trying to steal was at least half the size of his but I gather they check out everything (quality over size maybe). <<Mmm, as stated...the red-leg wanted/wants to consume the smaller crab. This is part and parcel when keeping marine hermits (very opportunistic predators…even to the point of cannibalism)>> Many thanks for all the info. I am identifying a lot of the critters in my tank now, thanks to you, and hopefully will be able to maximize their captive experience. <<Excellent my friend...do keep reading/learning>> Kaz <<Regards, EricR>>
Re: Hermit Crab Predation - 09/10/06
Thanks so much for your time Eric R. <<I'm happy to share>> As the Red-legged Hermit stopped rushing around and showed no signs of aggression (innocent until PROVEN guilty) and the Blue-legged managed to get himself a third of the way across the tank to perch on top of his favorite frag (which is half the size of him) I decided to just monitor things. <<Sounds fine>> In the meantime, I saw a bit of white stuff like a short hair and when feeding the clown realized the cleaner shrimp was not eating as it usually does; no interest at all in food. <<Unusual behavior...these shrimp usually become quite "interested" at feeding time>> Not so the Blue-legged hermit. He was chomping down on the ghost skeleton of the shrimp, completely unmolested by the Red-legged hermit who took no interest whatsoever. <<Not unusual behavior...but doesn't mean the red-leg wasn't trying/won't try again to eat the other hermit. Predation upon one another is quite common...especially in the unnatural confines of an aquarium...nothing really you can do about it in the long run>> Yeah, my shrimp has done a successful molt (he's three weeks old to me) and has just regained his appetite. <<Ah...good>> I'm wondering if the legs of the crab were part of a messy molt? <<Is possibility, yes>> I haven't properly witnessed a molt but there seemed too much flesh and color to the remains. As Blue is more active now, I can see he has two eyes, two small red bent bits, two long straight red bits, two functioning claws (so, tiny yet clumsy looking!) and numerous functioning legs. I'm trying to identify Blue properly (been searching pictures for hours) as I am not sure he is a Standard or Electric blue hermit crab. He has a white stripe on dark colored legs and red feelers. His eyes are too small to see properly and he has a shell in a built-in eyeshade style to boot. His claws are dark with small light/white spots. <<Try a Google search of the NET re those common names>> May I ask another question? <<Certainly>> Is it possible to get MH or VHO spotlights for small areas of a tank? <<Yes...a small pendent fixture would likely suit...have a look here: http://www.marinedepot.com/aquarium_lighting_metal_halide_icecap_spotlight_pendant.asp?CartId=>> I think I may have some hard coral on a piece of live rock along with some lemon yellow, possibly Zoanthid or Palythoa..(button) polyps. <<Cool!>> I found a picture a couple of days ago but 8 hours of searching have failed to get me to the right spot again. <<Try keyword searches on Google or a similar search engine>> The coral looks like closed up zoanthids in a yellow ochre color. The polyps blend into a substrate of the same color. They are about 1/2 mm across each. I think the name of the coral began with B. <<Mmm, don't know...could be many things>> Many thanks again. Kaz UK

911--Dottyback eating hermit crab 7/7/06 Hello! Thank you for this amazing website. I have learned more than a lifetime of experience from you and I love Anthony's and Bob's books. I have kind of an emergency because my Strawberry Dottyback just ate my reef hermit crab--tail first--and the claws, etc. seem to be stuck in his mouth! What should I do? Remove the crab? I can send a picture if you would like. Thank you! Jessica <Mmm, I would try to extricate the crab exoskeleton bits here... two nets to catch the Dotty, gentle pulling with tweezers/forceps... Good hunting! Bob Fenner>

Something strange this way cometh... too much incompatible life in too little water... nanos, clownfish f' 6/10/06 Hello Crew! <Tom> So, something very odd is going on in my 24 gal Aqua-pod. I finally have my water parameters in the right place (PH at 8.0 and rising, Amon 0, Nitrites 0, <20 Nitrates, Cal 400) and all is happy. But, first my tank inhabitants. 2 Clarkii Clowns, mated with hosted Sebae. <Not enough room...> 1 Yellow tailed Damsel 1 sally lightfoot 2 peppermint shrimp 4 snails 4 blue crabs - 2 small, 2 very small - well at least I had them! All my blue crabs are missing - as far as I can tell. My male Clarkii and my Yellowtail Damsel are getting very very cozy and the Damsel keeps clearing the bed of shells I have in the back of the tank. (My female Clarkii still is very 'mean' to her male mate) <Will likely kill it soon...> The last odd thing is, I have 2 inches of shell substrate and about 1.5 inches of LS. For some reason, more and more shells keep ending up on top of the sand, and making the sand look terrible. :-( <Are less dense... will tend to "surface"...> I'm all for letting my inhabitants live and let live, but this is all very confusing / fascinating! Any ideas? Thomas Simpson <A bigger system, less tasty tankmates. Bob Fenner>

Coralline Algae and Hermits a-chomping 5/2/06 Hi Crew and thanks for helping all of us! <Hello back at you! Jodie here once again on this fine and stormy evening.> We have a 30 gallon tank with 30 pounds of live sand and about 40 pounds of live rock. We have 4 very small fish and around 30 hermit crabs. <What kind?> In spite of all of our efforts, we can't get the rocks to "purple" with coralline algae. A year and a half ago, we added a 120 watt lamp. The rocks look darker now, but not purple. My wife has noticed at the local fish shop that the tanks that have nice purple rocks have no hermit crabs. She's convinced our crabs are eating the coralline algae. <She could be right...> I insist otherwise. <...but so could you.> Which one of us is correct so we can settle our wager? <Hermit crabs, especially red-legged ones, could be eating the coralline if they are lacking in food. I would check your parameters first though, before blaming them. Low magnesium levels can hinder coralline growth, as can nuisance algae, poor water circulation, urchins, etc.) Thanks for all of your great advise! <Sorry I couldn't definitively settle your bet. Too many variables for me to make a solid judgment. Cheerio, Jodie> Charlie

My Scarlet Crab, Kujo ... Anomuran comp. 4/25/06 Hi WWM crew, <Thuy> I've enjoyed reading all these problems, and learning from other ppl's marine woes for over a year now. Anyways, I've looked at fish magazines, and your site for information on scarlet hermit crab behaviors, and have seen that they are supposed to be the most docile and peaceful of all the crabs. <Operative term: "supposed"> Well, this scarlet crab I adopted from an LFS a while ago was caught in the act of eating my cleaner shrimp, during the shrimp's molting phase. <Bingo> She was named Rosy, <And Tasty Rose after?> before the incident, and seemed like a great addition to the tank along with two other scarlets and about 3 blue legs, in a 46 Gal (bowfront), w/30lb LS 10lb crushed coral, unsure the Lb of LR, it was a while ago, from a split of a 100lb LR purchase with somebody else at its initial start up. [Tank mates, YTang, (Nemo) Perc, maroon (Marlon), <Bad choice here> Talbot Damsel (Talby), Dori (Ytail Damsel), Dori Jr/DJ (Blue Tang), <Will need more room...> bi-color Blenny, 40 snails-maybe less, frogspawn, mushroom colonies, Kenya tree, eaten Xenias (by the damsels)]. Anyways, so Rosy was given another chance to play nice, and another cleaner shrimp entered the tank. She seemed to ignore the shrimp for awhile, but sure enough, a couple weeks later I saw the shrimp body in her claws, and a molted shrimp shell on the other side of the tank--Pure Evil. <Mmm, no... "pure opportunism"> So I had to part with Rosy, (now nicknamed Kujo) and I gave her to a friend who started another tank, and didn't plan on getting a shrimp. I visited recently Kujo and she's huge, or looks it. She took for herself a shell that's way too big for her, when there are other shells, around. She drags herself all over, and bullies the snails, pushing them away from what ever spot they're congregating at and squeezes herself in the middle of all of them, picking at whatever sand she thought they were nibbling at, my Gosh she has Attitude.! So anyways... I don't know if Rosy (aka Kujo) is an isolated case or something, but she is a character, with a ton of social skill issues, but she is one heck of a clean freak. Her other scarlet pals Pucca, and Kitty are angels compared to her. <Who knows what even species?> So I'd advise anyone to observe your potential adoption of a scarlet hermit crab very carefully, spend at least more than the 10 seconds I spent picking crabs. Actually I think Scarlet crabs were a hot commodity in my area during that time, and I adoption all three that I saw in a tank, after checking in with 3 LFS' around me. =T <Again, I am not a fan of using Anomurans or Decapod crabs in almost all captive marine settings... reasons repeated many times on materials archived on WWM. Bob Fenner>

Cirrhilabrus Wrasse Compatibility with Hermit Crabs 3/3/06 Thank you WWM Crew for all your past advice. Two of my Red Legged Hermit Crabs (Paguristes cadenati) disagree with the common fact that Cirrhilabrus Wrasses are "Reef Safe." <Heee heee... who's "right?"> My Social Fairy Wrasse (Cirrhilabrus rubriventralis) must have gotten bored and ate up some free-range fish food. <Yee hah! Get along little anomurans!> It was no great loss (But a great show.) I post this experience just so others can know and so they will not get terrified if one of there Cirrhilabrus Wrasses takes down a tank mate. <Thanks> One thing, he has never eaten one of the Blue legged hermit crabs (Clibanarius tricolor) ??? <Not as tasty? Might if hungry enough. A point in lesson here: "All animals, as species, individuals are only to some degree "safe" or no"... Thank you for sharing. Bob Fenner>

Hermit Crabs - 12/31/05 Can different species of hermit crabs be put together, or will they fight? <<Many of the; in my opinion, dubiously labeled "reef safe" hermits will coexist...for a time. All are predacious...when food/shelter (shells)/territory become an issue, only the strong will survive. EricR>>

What To Do With A Hermit Crab? - 12/19/05 Hello, <<Howdy>> I bought some rock fragments yesterday (along with some Chaetomorpha) for my refugium (small CPR back of the tank style). The refugium has been set up for about 6 weeks with only a filter pad in it (I have been meaning to get around to setting it up, but a few things got in the way) with the goal of increasing pod production for 2 of my fish who enjoy them. <<ok>> This morning I noticed that one of the 'fragments' is a hermit crab (red, in a 1" by 1/4" shell). <<Mmm, not a fan of crabs...>> I saw the shell yesterday, but assumed that the guy at the LFS knew it was empty and threw it in with the rock so I did the same. <<Yet another testament to quarantine.>> I want to know if you advise (1) keeping the hermit in the 'fuge (will he just eat all of the pods? is it big enough for him?); (2) moving the hermit to the main tank; or (3) returning the hermit to the store. Okay...I don't recommend crabs in a refugium. Don't let the little tyke's size fool you, hermit crabs are voracious, opportunistic predators that will eat most anything. The purpose of the refugium is to provide a "refuge" for the critters you want to breed and prosper, introducing a predator seems counter-productive, don't ya think? I don't like them in reef tanks for the same reasons...eats anything. My choice would be to return/trade the crab.>> I don't have any corals, but have 1 polyp, several sea squirts, 2 Astrea snails, several tiny starfish, many pods, one small crab, many small feather dusters, bristle worms, another type of worm that I have not yet identified, some algae, one Flame Hawkfish, one small False Percula, and one adult Orchid Dottyback in a 45 gallon tank with aprox. 30 lbs live rock (slowly increasing) and a 4 - 4 1/2" DSB. All of the livestock but for the fish and snails have hiked in on the rock. <<Neat>> I know that hermit's are not reef safe from reading the FAQs, but would a hermit go after the small stars, feathers (probably yes?), snails, worms and squirts? <<Always a possibility.>> I know that the hawk could go after shrimp; he hasn't touched the crab... would he go after a hermit? <<Another possibility...though probably not likely.>> I have read many of the FAQs but sometimes the more I read the more confused I become (the more I learn the less I seem to know.) I guess my instinct is to return him but want to know a pro's opinion. <<Not so much a "pro" as "student of the hobby"...along with a few decades of wet carpets behind me. <grin> >> Now that I think about it, I have a second question. I have many many white squiggles on the back of my tank and on the powerheads to the fuge and protein skimmer. <<Likely Serpulid worms.>> They appear to be baby feather dusters (mostly red). <<Yep>> Is it ok to have so many (I'd estimate more than 100) in a 45 gallon tank? <<No problem...self limiting.>> Would overfeeding lead to a drastic increase in their number? <<Possibly...but unless they are problematic (clogging filters/powerheads) I see no reason to fret.>> I don't have much algae, a bit on the rocks and the back of the tank here and there, which I mostly leave be for the snails to harvest (mostly green hair with some red velvet on one of the rocks.) I routinely scrape down the front and sides of the tank but leave the back to grow (coralline is starting to appear in spots.) Generally I try to enjoy the tank and the tiny inhabitants, stepping in only if something is out of line. <<Nothing out of line here that I detect.>> Maintenance is 10% weekly water change (Sat) and supplementation with B-Ionic (Sun). <<Unless you have some animals with a high demand for calcium (you didn't list any) you should be able to get away with just the weekly water change and save your money on the B-Ionic.>> Thank you. Jen <<Very welcome, EricR>>

Marine Hermit Crab Die Off and Stocking Density (Give, Your Crabs a Shell) 11/28/05 Hello Crew, <Hello Tom.> I really appreciate all the help you've given me over the last couple years...thanks! <Glad you have found us useful!> Today I'm hoping to get an informed opinion about what might be happening to my hermit crabs. <Okay.> My tank is a 30 gallon with a two-inch Fire Shrimp (Lysmata debelius), a Yellow Clown Goby, and a Firefish. It also has a small crab (size of a dime) and probably a very small brittle star (all I ever see is his arms sticking out of a hole in the rock a quarter inch or so). These latter two hitchhiked in on the live rock. <Good stocking choice so far, but watch out for the hitchhiker crab or at least try to i.d. it, could turn out to be something large/predatory in the future.> The tank has a larger grouping of rock on the left, and a smaller grouping on the right, with a few inches separation in the middle. The Fire Shrimp lives in the left rock grouping, basically all alone. Everything else lives in or on the right rock grouping. I only mention this because it seems so odd that it might be a clue. About two months ago, I ordered a dozen Dwarf Red Tip (Clibanarius sp.) and a dozen Zebra (Calcinus laevimanus) hermit crabs to control algae. I received generous counts, and actually started with about 30 hermits. As of today, I can count only 11 hermits. There may be a few I can't see, but 19? <Honestly Tom I think the reason for this hermit die off is the original stocking density. These animals simply aren't built to live a crowded arrangement like this but they are plagued by retailers recommendations of 1 per gallon, which is quite irresponsible (not you them). Anyway there are probably a few contributing factors including fighting over shells and insufficient food. Unless you were target feeding the hermits its unlikely they were able to survive simply as detritivores or scavengers. A more appropriate stocking level is 10 or less.> I also believe a hitchhiker snail has disappeared. <Possibly killed for its shell.> So, what do you think is happening to the hermit crabs? <See above.> Tom <Adam J.>

Did My Hermit Crab Kill My Bird Wrasse? - 11/27/05 I have a very large hermit crab (about as big as a fist). <<Yikes, that's a real monster! I hope it's housed with equally large(r) fishes.>> Yesterday my 5 1/2 inch green bird wrasse seemed to be as healthy as always and then 4 hours later it was being eaten by my hermit crab. <<Yep, not large enough (the fishes).>> I would suspect that the crab must have found him dead but the fish had a habit of lying around in the sand when he wasn't looking for food. He strikes me as one of the easiest fish to catch (for a hermit crab anyway). Should I get this crab out of the tank? <<I would, unless you plan to keep large/aggressive fishes that won't run the risk of falling prey to this ferocious predator. EricR>>

School Question re: Hermit Crabs 11/10/05 I am doing a project about hermit crabs. I can't find the answers to these questions. Can People eat hermit crabs, and do they? <Yes, have seen places in the world where folks caught, ate Hermits for food> <<Ok, ew.>> What eats hermit crabs in the wild, besides other crabs? <Large fishes like sharks, rays, Triggerfishes, large wrasses, groupers... Bob Fenner> <<Don't forget our favorite, Mantids, not to mention octopi and possibly other inverts. Marina>>

Unusual reef safe hermits 8/22/05 Hello WWM crew, Your website is super informative and I've been browsing it for a very long time now, and I've finally got a question! I was looking on your hermit crab (SW) site and it lists reef safe hermit crabs; my question is... Is there any more unusual or even "different" (maybe even "rarer") species of hermit crab which are also reef safe? I really like hermit crabs, and a variety of them! Thank you, Nicole <There are many species of hermits, although relatively few are regularly imported. Since most of those that are regularly imported are collected for being attractive, you probably won't find too many attractive ones that are "rare". Your best bet is to watch your local retailers for one that you find interesting. Reef safety is a subjective term. I personally don't keep any hermits (even those that are supposed to be "reef safe") because they all will eat just about anything they come across. Best Regards. AdamC.>

Six-line wrasse and crab compatibility 8/4/05 Hi, <Hello, Jed> I recently inherited a six-line wrasse from a friend getting out of the hobby. Being the fool I am I happily took the wrasse knowing little about it other than it was reef safe and moderately aggressive. The aggression should not be a problem but I now have learned that a few lined wrasses will eat hermit crabs. Now here is my problem I have a small number of scarlet hermit crabs (five to six) and I am worried about them being eaten. I can't give the fish back because it means a lot to my friend that I keep her favorite fish, and she wants visitation rights. The wrasse is only two inches long but I am still worried that the wrasse may eat the crabs which I also want to keep. So do you think a two inch six-line wrasse will pose a threat to my scarlet hermit crabs? <Jed, the six lined wrasse should be just fine with the crabs, they are reef safe. James (Salty Dog)> Thank you very much,<You're welcome> Jed

Hermits and Corals... incompatibility 7/13/05 Hello, hope all is going good. I currently have a 150 gal tank; pretty well established, I believe. About a month ago I acquired several additions for my tank, which totally rocked my tanks world. This guy was getting rid of his 30 gal. 45 lbs of live rock, and I have been trying to properly ID all the corals, so far so good. There are trumpet corals, green star polyps, yellow polyps, a green open brain coral...not doing to great, wasn't when I got it. Another coral which I think may definitely be dying, If you don't mind I will send a pic and maybe I could get some guidance on that one, I think maybe some sort of brain, etc. There are others along with a few fish and several snails and little tiny hermit crabs. etc. The idiot was going to literally throw the tank away....set it out with the trash with all living creatures in it! I am a softie for animals, I thought they would have a better chance at survival with my minute, yet growing rapidly, knowledge than outside by a trash can. I was planning to slowly work my tank into a reef tank, but it sort of happened over night and I've been racking my brain trying to find info on my new friends. Which I don't mind I love the learning process of it!! But I'm stuck now and maybe you can help. I already had two jumbo hermit crabs (I'm sorry I'm not sure if that is the actual name of it or if that's what the LFS called it, I've tried to properly ID it but all I get are pictures with no names by them except "hermit crab") they are almost the size of a golf ball, just little monstrous tanks :). They are great to watch, except for when I watched them destroying the star polyps. There was a patch of rock covered in the polyps... just a tad bit of green algae around a few of the polyps, and now there is a bare patch with nothing but rock. I was watching one of the jumbo hermits just to watch and I noticed it munching away at what first appeared to be algae. Then I saw it ripping up the polyps! I don't know if they were actually being eaten or if the crab was trying to get the algae off. <Large hermits can/will eat most everything> I'd hate to see the big hermits go, but I would rather save the corals. I haven't found that hermits weren't reef safe, (I realize many are) But I guess what I'm getting at is....Do I need to remove the hermits if I want to save my corals, or should I consider another path, like maybe feeding the ever hungry hermits more food? <I'd remove these.> I thank you so much in advance...and I am trying to learn this at a fast rate to give my animals the best care they deserve! Codie <Steady on... keep studying, you'll do fine. Bob Fenner>

Hermit Crab Compatibility - 05/24/05 Hello, I'm starting a reef tank and I have 1 red hermit crab that has molted 1 time and 2 electric blue crabs 1 stays small the other molted 2 times and has gotten big should I worry about this crab hurting me reefs? I do have corals already hammer, frogspawn, candy cane, polyps, flowerpot, Christmas trees, feather duster,1 yellow tang, red Firefish, red spotted blenny mushrooms. thank you for your help! from R.G. <Any crab is a risk in a reef in my estimation...though much debate for and against is to be found. Have a long read here http://www.wetwebmedia.com/hermitcompfaqs.htm and with the associated links in blue. Regards, Eric R.>

Hermit Crabs In A Reef...Are Any Of Them Safe? - 05/22/05 Hello, <Hey!> I have recently begun reading your site, and was somewhat shocked to read that you do not recommend keeping ANY crabs in a reef system, since almost every dealer or website or individual reef keeper I know of states that they are reef safe and are the best option for cleanup crews. <This is not everyone's view here, but yes, a few of us (myself included) choose not to recommend/include hermit crabs in our systems.> Some places recommend somewhere in the vicinity of 1 per gallon. <Yeah...places that SELL them.> I have used them in the past (my reef tank is down at the moment) with a few corals and not noticed any problems, but then I wasn't looking for them. Do you truly recommend forgoing crabs completely as cleaners, or are there a few limited species that work well? <It's a matter of preference. I choose not to employ hermit crabs for the reason they are voracious opportunistic omnivores that have a tendency to "snack" on other desirable organisms.> What instead should be utilized for cleanup in the complete absence of crabs? (The system I am preparing to set up is 135 gal BTW) <Proper setup/maintenance practices, an effective skimmer, frequent partial water changes, judicious feeding practices, etc.> Specifically, I have a great deal of affection for the Staghorn hermits. Are these any better/worse than your average dwarf hermit in a reef? <Probably no better or worse, though they are reported to be more secretive and delicate (more sensitive to water conditions).> Thanks, Frank <Regards, Eric R.>

Stocking "cleaning crews" (hermits, snails), lighting coral help on WWM Bob, Thanks for the reply. I've read the WWM sections about inverts and the quantity, and also noticed that you're not such a fan of these cleaners. <Yes> To be more specific, I have 20 blue leg hermits, 10 red leg hermits, 3 margarita snails, 8 Cerith snails, 5 Astrea snails, 1 peppermint shrimp, 1 cleaner shrimp, 1 serpent star fish (only 4-5"). Can you give me your insight on why you don't agree with so many inverts? <In a small volume (your 24 gal. cube in this case) the hermits often "cross the line" between being scavengers to predating desirable organisms... including each other... The snails die, en masse sometimes... and their dissolving takes most everything with them...> I read somewhere that this many inverts was the perfect amount to keep an almost maintenance free tank for a 24 gallon tank. Were they just full of B.S. so that they can sell their product? <Mmm, well.... there is at least a "difference of opinions" here... there definitely are a bunch of "pro" cleaner uppers as well as "cons"... Each must decide for themselves... but if you take a look in the wild, you will see there are few parts of natural reefs so arrayed> Also, currently I don't have any corals, how many hours should the lights be on? And how many hours if I do get corals? Thanks. Perry <Please put the terms: "lighting corals" in the Google search tool here: http://www.wetwebmedia.com/ Bob Fenner>

- Do Clownfish Eat Hermit Crabs - Dear WWW crew; I currently have a 45g corner tank. I have 2 questions. First I think my tomato clown ate my hermit crabs. The crabs were rather small (the shells were less than the size of a pencil in diameter and about 1/3'' long) blue-legged hermit crabs. Shortly after I added them, the clownfish would pick the shells up and drop in another part of the tank. He seemed to be having a lot of fun. I moved them and tried to hide them from the clown, but I never saw them again. <You may want to check your tank at night... often once the crabs know they have predation pressure, they will go into nocturnal mode.> There is also a bi-color Pseudochromis in the tank who was quite interested in what the clown was doing. Could either have eaten them? <Anything is possible, but this isn't a known staple of either's diet.> I'd like to add a couple more but I'm afraid it would just be an expensive snack. My second question is what can I add to the tank. I tried a 6-line wrasse. I had it for about 2 weeks and it died suddenly in the QT tank. The QT tank is 2.5g. <Much to small for quarantine.> I was replacing the water with tank water every day or two. The water is: 0 ammonia, 0 nitrite, 5-10ppm nitrate (I can't seem to get rid of it), salinity 1.0235, PH 8.3. The tank has been set up for 6-7 months. I'm afraid to try another, because I don't know if it was a bad fish or I killed it. <Well... tank is so small that even water changes represent drastic chemical changes... would advise you use at least a 10 gallon tank to quarantine such a fish.> The clown is about 2 1/2" and the Pseudochromis about 1 1/2". There are still 2 red reef hermit crabs that are about 1/2" to 3/4" and apparently able to fend for themselves. Is there any other small fish that are good for beginners (my first saltwater tank) that I can add? I was thinking either bi-color blenny or algae blenny. <Would be a good choice.> Should I try another 6 or 8 line wrasse or is there a better choice? <Well... given the size of this tank, you may find a six line wrasse gets a little grumpy in time.> What are your thoughts about 3 green Chromis? <That would also be a good, peaceful choice.> I plan on adding these one at a time over a couple of months, except for the Chromis of course. I'd like to have around 4 small fish in the tank. <And that would be a good place to stop.> Thanks so much in advance, Dawn <Cheers, J -- >

Hermit crabs Hey Bob, I have a 75 gallon tank with a lot of fish and things, and I have a lot of hermit crabs. Some are red legged and some blue legged and some of the hermit crabs keep eating my coral and killing it. I can't really tell what type of hermit crab is and I want to get rid of the ones that are. Do you no what types of hermit crabs do? Thanks a lot, Taylor <Taylor, MikeB here. I am not sure what kind of hermit crabs you have but the ones that I find work best in a reef tank are the Blue Legged. There are some hermit crabs that have red legs that can eat coral. I would stay away from decorator crabs and arrow crabs. Good Luck. MikeB.>

Missing hermit crab!!! Help! what I really need to know is do hermit crabs eat each other? <Mmm, yes... almost all "will"... and some larger species definitely will!> I had 3 crabs, baby, in a 10 gallon tank, one came out of his shell a week ago and died and I noticed the other little one came out of his shell but is nowhere to be found. where did he go. he is absolutely, positively gone!!! did the other crab maybe eat him or what? help!!! <Mmm, do you have spare shells for your Hermits to switch to? You should... when they molt, Hermits will abandon older, smaller shells for larger... and are quite vulnerable to attack at these times. Bob Fenner>

Hermit Crab non ID... and too vague response Hi, I have found many answers to my questions on your site. You guys are great. I have a little hermit crab. His shell is about 1 and a half inches wide. He has brown and tan stripes running down his legs. He was a gift and I was wondering what type he is and if he is reef safe. I believe he is from the Atlantic, but not positive. I would appreciate any help, a picture is attached. Thanks!<Mike, most hermit crabs are reef safe in a sense. <<What? I would NOT make this statement. RMF>> This guy might not be safe with smaller hermits (blue legs etc). I would keep an eye on him for a while observing his behavior. James (Salty Dog) <<James, where's the ID? Read the query, please. RMF>>

Help - a killer in my tank - hermit crabs MIA Dear Crew <Peter> I have been reading your site for some time tonight, but ... ... who has been eating my small blue legged hermit crabs? <Ooooh, I do so love a mystery!> I shone a light in the tank late last night and saw only two 2-3" long, dead straight, spaghetti like feelers. After a few seconds in the light the feelers slowly spiraled away into the rock. <Mmmm, maybe the polychaete worm butler "did it?"...> Is this fascinating or nasty and should I dump that piece of rock?
<Hello Peter. Do not dump the rock. The worms are probably innocent. Your hermits are probably in a rock crevice eating trapped food particles> James (Salty Dog) <Oh... I see our new Crewmember James has answered your query...> I need help with this one. I am new to the hobby, and did not realize what goes on after the lights go out. Thanks a lot. Peter Hosier <I agree with Salty... let some time go by... and if you can, continue to monitor that worm, other possible hitchhiker predators and consider baiting, removing them. Please read here: http://www.wetwebmedia.com/polychaecompfaqs.htm Bob Fenner>

Hermits and busted up feather dusters Hi Bob, I bought some really cool feather dusters and one of my hermit crabs climbs all over him. He then broke the tube near the base and started munching on him or it seemed that way. Well I tried to move the feather duster to a new location but as I dug him up, the feather duster dropped out of his tube. He's all exposed now. What should I do, What should I have done as I have more feather dusters? Any help would be appreciated. Thanks P" <Hello, MikeB here to help. I would recommend removing the hermit crab in the future. The feather duster will probably not make it without its protective covering. I wouldn't move any feather dusters once they have attached themselves to the live rock. Good Luck. MikeB.>

Hermit Crab, Coral Compatibility Thanks so much for your speedy reply. I took your advice. Instead, I'm beginning with coral, some simple polyps. I noticed my electric blue hermit crab on the rock where the polyps are growing. These crabs won't eat the coral will they? <No, hermit crabs don't generally bother corals><<Mmm, this is a minority opinion here. RMF>> James (Salty Dog)

Will His Hermits Become "Feeder Crabs?" (9/8/04) Hello All, <Hi. Steve Allen Today> Question as it is simple... I love my 100 plus blue leg hermit crabs. They keep the hair algae in control... well actually they removed it all. I wanted to buy a 12 line wrasse (looks like the 6 line but green in color) what will be the chance that it we decide that blue legs are taste? <Members of this genus are well-known as predators of crustaceans. I'd say there's a pretty good chance it will enjoy a hermit crab banquet over time.> I know anything can happen with fish... My Lemon Peel Angle suddenly took out my cleaner shrimp, weird hey? <Edible is edible.> Took me awhile to figure out what was killing them until I purchased another one and "BAM" took the eyes off <ouch!> and the dinner was served. I would like to know if I get the wrasse will the hermits days be numbered? <Quite probably.> Or am I better not going there and let my hermits keep the hair algae out of my tank... <If you love your hermits and appreciate their handiwork, why take a chance? Go with something that has a much lower probability of munching them.> Thanks much, Paul

Hermit crab risk and possible Aiptasia eating starfish 8/6/04 Hi Nicole here. Only have one coral and it has to go back due to not enough lighting and can't afford to get more just yet (sad) but anyway would hermit crabs be a problem for feather dusters if I get them soon? Don't really care if I have to remove them they just eat crap on the bottom and keep tank clean. Cleaned my canister filter today and found only two Aiptasia. Found one large one behind a rock but otherwise no sightings, tank one was on substrate so easily removed likewise filter ones. Got cowry after Aiptasia disappeared so has to have been starfish then. They are just little ones about 1 inch across that I got from local boat ramp, nondescript brown mottled. but damn they do a good job keeping the tank clean and obviously Aiptasia free too, yay!!!!! <Your hermits are probably fairly risky to your feather dusters, especially if not well fed. I would encourage you to test your theory that the stars ate the Aiptasia. If they do, you may have a lucrative cash crop! Best Regards. AdamC>

Hermit crab and other invert info 8/1/04 More info than a question in case anyone's interested. I have a hermit crab that like eating my closed brain coral, b*st*rd it is slowly disappearing so hermits are a problem in reefs. <I am fairly sure that you will find that most of the crew that replies to marine and reef queries are not fans of crabs of any kind. I generally advise against keeping any. They are far too destructive for their benefit.> Also I had quite a numerous Aiptasia problem on live rock got a few with Kalkwasser but only the bigger ones now there is not one to be seen. There were less every day until now there are none yay! Must have been eaten by something, <I would love to know what! Peppermint shrimp are known predators as are Berghia nudibranchs (not what you describe below). Other, less specialized predators (some starfish, some predatory snails other shrimps, etc.) are probably very risky to also eat corals.> in my tank I have damsels (lemon, sergeant major, blue/yellow and 2xblack with eye spot on tail) small wrasse similar to Christmas wrasse, two purple/orange/black nudibranchs, small brownish mottled starfish, cowry, pistol shrimp, four or so hermit crabs I think that's it. So one of them eats Aiptasia! Hope you find this of use. <Out of the bunch, I would only suspect the starfish or cowry. The nudibranchs are a very very tiny possibility, but most of them are very specialized feeders (sometimes down to the exact species of coral, sponge, etc. that they prey on!) Thanks for sharing, and please update us if you hone in on your mystery helper! AdamC>

Hitchhiker ID/Refugium/Snail reproduction - 2/26/04 Hey Crew! Thank you all for such a great site. I wouldn't have made it this far without all of you. <We wouldn't have made it this far without your questions. So, thank you> I have attached an image file (not the best picture in the world) of a hitchhiker that has shown up in my tank. If anyone has an idea of what this is I'd greatly appreciate the knowledge. <Definitely an anemone from the family Actinodendronidae See here: http://www.wetwebmedia.com/anempt2.htm> My second question, is it okay to keep hermit crabs (blue legged variety) in a refugium? <I don't like the idea of putting hermits in a refugium as they are so omnivorous that they might eat anything and everything> My crabs, although great at keeping the sand on the bottom of the tank clean, are becoming pests to my soft corals and I would like to move them into my above tank refugium. <Really? I haven't heard of Blue Legged hermits bugging soft corals> The refugium is about 10 gallons and has a 4 inch sand bed and contains Chaetomorpha, grape and feather Caulerpa, and probably some other plant life. I got the grab bag of stuff from the LFS. <Sounds good. Do you keep lit 24 hours a day?> Thirdly, is snail reproduction normal in a healthy tank? <Yes. Pass them around to friends and reef club members.> Thank you kindly, Tony Hambley

Large hermit crabs My LFS has 2 different hermit crabs. Both are about the size of your fist and red in color. One was just called a "large red hermit" the other was a "fuzzy red hermit". Do you think that these crabs will harm any small fish and will they eat any hair algae? Thanks in advance. <Do think these large hermits will be trouble... try eating most any type of other animal you have in your system... maybe finish up with a bit of "algal salad" with their meals... but not as primary food. Bob Fenner>

These Crabs Won't Grab! Quick Question: <Go for it!> I bought 10 small (all <1"; most <1/2") hermit crabs at my LFS to help clear diatoms & detritus from the substrate of my 80G FOWLR. Before putting them in my tank, I became concerned that they could pose a threat to my yellow-headed Jawfish and my Firefish. I haven't put them in yet. Is there any actual cause for concern? Thanks, Steve. <Well, Steve, if they are indeed the "herbivorous" varieties that are commonly used for algae control/scavenging, I wouldn't worry too much. Some people implicate them in coral munching, etc., but I think that most of the "damage" they do to corals (if they do any) is a result of them "walking" over the corals. Most of these guys stay really small, and are quite content to scavenge what they can. I have a number of these in my reef tank (which has several bottom dwelling blennies), and I've never had any sort of problems. Now, that's no guarantee that yours will be perfect citizens, but I'd feel comfortable with them. Good luck! regards, Scott F.>

Urchin & Crab Hey guys- I got a fairly large red hermit crab, has black hairs, white spots and fits in a large Mexican turbo snail shell. my question is, I picked up a small "orange eyed" black urchin, and it looked like the crab was going after him last night. this morning I can't find the urchin, but did see about 10 spine clippings in the sand were the hermit crab was. Are crabs natural <Many are> Is it possible that the crab killed the urchin, or is it more likely the urchin is hiding? <You can look about...> should I remove the crab? (the crab is ill tempered, eats all the snails and what not). Thanks for all the help, Justin <If you intend to have such animals... Bob Fenner>

When Good Crabs Go Bad...Live on WWM 3/19/03 Hello!<Hey! You got Phil tonight!> My red legged hermit ate my blenny and a snail.<Oh no.. are you sure.. did you see it happen?> I first suspected my fiddler crab, but I read they don't kill fish, because they are herbivores. My question is, How the heck he could have done it (to the blenny) with his little claws (he is 1/2")? He ate the whole thing.<I doubt that he killed it. More likely the fish died and the crab(s) ate the remains. I have seen that happen, but have never seen a crab kill a fish. It happens but I doubt it in this case. Good luck and sorry about your loss!> Thanks<No problem! Phil>

Faviid eating hermit crab! LPS with a big appetite 3/16/02 Woke up this morning and found that my Faviid had found some dinner. Cant believe that there mouth can open so wide. There goes one of my blue legged crabs. <yikes... cool picture though. Shawn... I'd like to use this picture with your permission in a future presentation or article perhaps. If you would be willing to give your permission, could I trouble you to send the original (full-sized) image to me at readingtrees@yahoo.com and copy it to here as well in case Bob would like to post/use it? If that suits you, please also include your full name as you would like to have it cited for credit (and an address to mail any possible printed copy to). No worries if you cannot share it, my friend. A very cool shot... indeed large zooplankton <G>. Expensive too if it becomes a habit... Ha! Best regards, Anthony>

Hermit crab ? Fixing to buy some hermit crabs and I was wondering if there were any another animals I could put in the aquarium with them. Thanks! <Are we talking about land or aquatic hermits. I would only keep land hermits with other hermits. If we are talking about aquatic hermits there are oceans full of animals that can live with them. -Gage>

A Crab-Eat-Crab-World? Just a quick question... <Hopefully I have a quick answer! Scott F. with you tonight!> I just put 1 electric blue hermit crab into my 55 gallon tank...he is about an inch and a half to two inches long and was told by the local fish store that he was no danger to my several small (1/4 - 1/2 inch long) blue legged hermits. Please let me know if you see a potential problem with this situation. Thanks much, you guys are great. <Well, in my personal experience, I have not had a problem with this species. However, I have noticed periodic cannibalism among various small hermits before. Sometimes, you just don't know for sure until they get together...I'd keep a very close eye on these crabs, and be prepared to intervene if you see someone sizing up his tankmates for a meal! Regards, Scott F>

Hermit Shell fell inside of Open Brain coral Anthony and or Crew, <Whassup> Sorry about using the old e-mail, but I could not get my browser to work for some reason. <OK> I have just started to read "Book of Coral Propagation" and both this web site, Bob's, and yours books have been very helpful but I have not found anything about this particular problem. I just noticed after feeding the fish tonight that a hermit shell is inside of my Rose Brain (Trachyphyllia geoffroyi), <Hmmm... minor correction: a Rose Brain is an illegal Atlantic genus of Manicina... you can a regular Open Brain Coral from Indo likely> I sure hope the coral had a nice meal? <agreed... but more like an appetizer> The hermit crab probably fell from the rock that is close by into the coral if I take my best guess. My question is should I go ahead an gently try and remove the shell <yes please... it could hurt this LPS in time> or should I let the coral try and push it out? <perhaps... try fresh figs> I know Anthony I left the door open on that last part LOL. <took a soft pass at it <G>> I have also attached two pictures for your viewing pleasure. <thanks kindly... it is indeed the deepwater (as red) Open Brain from Indonesia likely> Thanks for your help. be Smiling <will do... I'm gassy> TTFN Sean <best regards, Anthony>

Live rock vs. hermit crabs >I have two 55 gallon tank and 45lbs. of Fiji live rock that is curing. In one tank I have 25 blue legged hermit crabs and in the other I have no hermit crabs. If I put half the rock in each tank will it be ok with the hermit crabs? >>I don't see why not. >I know that they are "reef safe" but at one time I had 10lbs. of live rock in the tank with 10 blue legged hermits and they ate the rock to death. The algae and growth was gone. >>Try feeding them directly, especially add a small chunk of shrimp, Nori, or the like (anything that will stay whole while they eat at it). This should provide enough of a diversion for them. Do remember to provide them a few extra shells should they get tired of their current "flat". >Also, what is you favorite way to set up a tank? I might be getting a 100 gallons and I'm not sure if I want to go with canister filter, wet/dry, or a good size sump. Thanks for all the help, Andy >>Well, since you're starting from scratch, I suggest looking into utilizing a refugium. I really love the natural methods of reefkeeping, and a 'fuge is one of the best. Start on our homepage, look in "marine aquarium articles", then in "set up". Just TRY shaking a stick at all that's there! ;) Best of luck! Marina

Hermit crabs picking at live coral Hi, I really appreciate all the information I get from your site. <Thank you for sharing your part today.> I was searching on the necessity of hermit crabs and couldn't find an answer to my question hence this email. I traded in my 40 gallon tank for a 25 gallon high because I move around at least 3 times a year and wanted something easier and cheaper to maintain. <Cheaper? Yes, Easier? Not sure about that one as the greater the volume in a system, the greater the stability.> I took my 30 blue legged hermit crabs in as well as all my fish except for the two percula clowns and my fire shrimp. I have not had any success in keeping my corals alive until I got rid of the hermit crabs, they kept crawling on and picking at them. I am maintaining a reef tank now and want to add a lot more corals. <Be careful how you define 'a lot' as with fish, corals need room to grow and feed without having chemical warfare with each other. Do research the different types of corals you are thinking about so you can avoid these problems and choose tankmates that will co-exist with each other.> My question is, am I required to have hermit crabs to control the hair and other algae on the rocks? <Certainly not. Water quality is number one in nuisance algae control. Regular weekly or twice weekly water changes will do wonders. Personally, I don't like the hermits and lean more to a diverse combination of snails. Astrea, Cerith, Trochus, Turbo and Nassarius> I don't think I should get another tang because my tank is too small for one. <Good call, you don't want fish that are much more than 3-4" when adult. With the 25 I don't think you want more than one more.> What would you suggest? <As per above, Don> Please help!

Little Blue I really enjoy your web site and find it very useful.<As do I! Ryan helping out today!> Can you house blue legged hermit crabs with red scarlet hermits? I have a 55 gallon reef tank with 75lbs of live rock. The store manager at the place I buy my products says one will eat the other. Is this true? <It's not unheard of, especially when competition for shells is fierce or the scarlet is much bigger. Many crabs are omnivores in the true sense- they'll eat anything. Could really go either way. Good luck-Ryan>

Coral Eating Crab (8-2-03) Hi, I've just noticed my red-legged crab eating/nibbling on my soft coral. The crab is about the size of Blue-legged hermits, but it's red and has one claw quite bigger than the other. I thought those crabs were reef safe...? :-( <They are supposed to be reef safe. Watch him some more to make sure he is actually doing damage, then if he is take him out. Cody> Thanks, Luke

Hermit shells? - 12/10/03 Hi, <Sorry for the delay> Love your site. <Me too> I check the Daily Q @ A frequently and it is at times as entertaining as informative as something like my 55 G reef tank. <Agreed> Which brings me to why I'm writing. <OK> It is my clean up crew. I purchased a Reef Tune Up Kit from Indo Pacific Sea Farms. <I am thinking of doing the same> This included a dozen Micro hermits (Calcinus sp.?) that seem to be doing quite well. <Good to hear> In fact, at least two of them have grown large enough over the past couple of months to inhabit snail shells about 2.5 mm in diameter. They don't seem to be harming anything and seem quite social. <very cool> In fact, two of the largest stopped to exchange compliments on each others choice of shells just yesterday. <Careful and watch them they could become very aggressive towards each other> I'd like to be a good landlord an make sure that I have a large enough variety of types and sizes to keep them in rentals and not fighting over choice mobile homes. <Agreed. More shells than crabs is a very good idea> Who supplies shell packs that would meet my (their) needs? <I would just go to your LFS and ask for some of the many shells I am sure litter their tanks. Or ask them if they can contact their supplier of inverts for various shell sizes for hermits. I am sure someone can oblige> And just how large might these critters get? <Should stay fairly small. Maybe about inch and a half or less> Should I contemplate a crab dinner somewhere along the line or say, perhaps another, larger, tide pool style tank? <No need> Searching your archives has been unproductive beyond the obvious advice to get larger shells. <Not anymore. Thanks for your question. ~Paul> Regards, Charlie H.

Hermit crab Hello again, As usual, thanks for all the answers you have given. My questions this time relate to hermit crabs. Are the Dardanus megistos (White Spotted) crabs reef safe? <Not IMO... get too big, hungry for my taste, worry coefficients...> You mentioned on http://www.wetwebmedia.com/hermitcrabs.htm that these are "reef hermit crabs". I ask this because the two I "had" sifted the substrate really well. I sold them off thinking I was better off with scarlet crabs. If they are reef safe, would they prey on the scarlet crabs? <You're better to have done what you did (is this English? Anglish?)... I would have traded the Dardanus in as well... they may well have sifted your Scarlets.> Thanks again. Aldrin <Be talking my friend. Bob Fenner>

Fish and Hermits/shrimp I haven't seen this on your site so here goes. I have a fairly large tank (250 gallon gross about 200 net) however it is tall at 48" and roughly round at 39" in diameter. <Neat> This gives me a bottom space of roughly 9 square feet a lot of which is taken up by aquascape. I noticed at night the fish will rest/sleep on the bottom. <Yes, the same as many/most in the wild> I would like to add some hermits/shrimp (I assume I can mix them) <Some species, yes> but my past experience with hermits indicates they are masters at finding anything edible sitting on or near the bottom. Should I be concerned about a batch of hermits disturbing what is now a fairly peaceful low stress community tank? <Read through the "Hermits" section on the www.WetWebMedia.com site Especially in light of my somewhat restricted bottom space for this size of tank? All fish are at least 3" long. Have your book but do not see any reference to this. <Many more to come... Bob Fenner>

Scarlet reef hermit w/ anemone (?) hi bob, I got this scarlet reef hermit crab; it appears that on the shell there is a tiny anemone (I think). I'm sending you a picture I snapped. what do you make of it? <A Paguristes Hermit and Calliactis Anemone from the looks of it> although the alleged anemone appeared to have its tentacles closed in the picture, it opens pretty widely and happily most of the times. when it's open, there's a clear center without any tentacles which led me to believe that it is an anemone. also when the crab roams around the tank and bumps its shell into rocks and other things, the tentacles retract. anyway, it's pretty cool and it seems to have grown larger as days go by. my question is, shall I attempt to remove it from its mobile home and give it a permanent home on a rock, or just leave it be on the crab's shell? <Leave it on the shell... not surprisingly, when the Hermit "switches homes" (moves up to a larger shell), it will likely move the Anemone as well> and what would be the best way to detach it from the shell if you think that's a good thing to do? thanks for your help! -Alex << scarlet.jpg >> You can see more on Hermits, my opinions on the www.WetWebMedia.com site. Bob Fenner>

Hermit crabs and snails Dear Bob, My basement filtration system continues to produce perfect water conditions with little effort. I am wondering about maintaining the so called "cleaner uppers" in my 150 gallon system containing fish and corals. I have put in Turbo, Mithrax, Trochus, Nerites, and Strombus snails as well as blue leg hermits and a hermit I can't find info on called "left handed" (they are black and white). Also, I have cleaner and peppermint shrimp. I have seen a few small bristle worms at night and there are plenty of copepods coming up from the refugium. After several months there are only a few of the Turbo snails left and plenty of the black and white left handed hermits which have grown much larger and taken over snail shells of various sizes. I have seen Turbos eating each other and eating the smaller snails of various species. I have seen the hermits eating a number of the smaller snails and smaller hermits. Mushrooms, bubble coral, Alcyonium, polyps, and SPS have been undisturbed but something is eating the new elegance Catalaphyllia?? <Could be... perhaps parasitic snails, predatory worms... or it's just doing what this species does: see: http://wetwebmedia.com/elegance.htm> I can keep adding these "clean up" creatures knowing I will have many empty shells. Are they needed in my system? <By and large, no... most are not found in the environment where the species hobbyists keep are...> Are those black and white hermits destructive to corals? (I can't find reference to this species.) <Can be> The snails do eat a great deal of the algae on the glass but I still have to clean it often do to the amount of ambient light. Bob, I don't see the Convicts on any of the compatibility charts. My three stay in their caves and leap out to grab food. They look like 2 1/2 inch eels! Are they destructive to other fish or corals? <No> Appreciative as always, Howard <Keep studying my friend. Bob Fenner>

Hermit crab Hi once again Mr. Fenner, Sorry to write you again today, ( I wrote you earlier about the Gammarus shrimp). I have 2 dark colored hermit crabs that I saw attacking one of my numerous snails for it's shell, so they were out of there. I've since put them in the first section of my refugium where there is no Caulerpa, or LR, except for some algae that was growing on the bottom. They have since cleaned this all up. My question is are they safe to put in the section with my LR, Caulerpa, and Miracle Mud, or will they eat the Caulerpa? <Too likely to eat most everything> I am hoping they can be put in that section to help clean up the pieces of Caulerpa that are no longer growing, bits of algae, etc... Thanks in advance, and again sorry for the numerous e-mails Greg N. <Keep your eye on them, your sump, algae... Bob Fenner>

Crabs and Triggers I hope you can help. I would like to know if the large red legged hermit crabs (almost fist size) would become a meal for this trigger. The trigger is 11 cm specimen. Secondly, would he be very aggressive towards large angels, wrasse and eels? <This species is a "toss up" temperament-wise as far as a "predictability index" goes with Balistids... It will likely harass, ultimately consume the hermit (let's say if/when it molts), but in an adequately large, well fed, filtered system, would leave the fish/groups listed alone. Please see: http://www.wetwebmedia.com/sufflamen.htm and the FAQs beyond. Bob Fenner>

Hermit crabs Bob, <Anthony Calfo in your service> I've got a problem with a marauding hermit crab in my tank. I have a 40 gal reef tank and I've always had a few red legged hermit crabs in the tank with no problems. About 6 months ago I bought 3 very small hermit crabs (1/2" long in the shell)...they have black and white banded legs and light gray claws with one being considerably larger than the other. One of these crabs has just killed his second snail, evicted the former owner and taken up residence. Is this common with this species and should I be thinking about getting rid of it? I have 5 other snails that I would prefer not to lose. Thanks, Chris Donovan <more often than not, hermits are opportunistic predators...when you get a bad one, it is not likely to get better. Pull 'em. kindly, Anthony>

Red legged hermits to control Aiptasia Dear Bob, <Anthony Calfo in your service> On the WetWeb site, you discuss Aiptasia control. One method was "red legged hermits" (Dardanus megistos sp???). <More often called the "White Spot Hermit, but the scientific name is correct and all that matters> You were kind enough to answer my previous question. One more if I may. Can't seem to find anybody that has used them. <they are not guaranteed to even eat Aiptasia, although it may be true. The information is purely anecdotal at this time> LFS can't give me any information on that type of hermit. Do you know of any place to get these guys? Is there a common name I could use? <yes, above... the "White Spot Hermit" from the Indo-Pacific... and don't expect to find them anytime soon... not often collected because the landed price wholesale is ten times what a similar hermit from the Atlantic costs here in the States> I have a 125 FOWLR and a DSB with lots of in-fauna up for about 9 months. Just got my first Aiptasia on a new piece of rock. (Came out after a couple of weeks). Any help would be greatly appreciated. Jeff <Jeff... relax, my friend. Aiptasia are only a problem in tanks with nutrient export problems (although many aquarists struggle with this). In well run tanks, they do NOT spread or populate. They do NOT grow from thin air (or water, as it were). They need nutrients. So... skim aggressively, do regular water changes, do not overstock or overfeed, be careful about what you import into the tank (nutrients through poor quality tap water, not thawing frozen food and discarding pack juice (DO strain frozen meats), etc). It really is an overblown issue. Like many aquarists I have had aquariums that had an Aiptasia that took more than a year before executing a single act of transverse fission! But I am also a maniac about skimmers and nutrient control. If you find the need for control later, since this is not a ref tank, it will be easy for you to find a compatible fish that eats them. Do apprise us of you inventory of tankmates if and when that time comes. Best regards, Anthony>
Red legged hermits to control Aiptasia (Steve's turn)
Dear Bob, <Steven Pro at your service this fine night.> On the WetWeb site, you discuss Aiptasia control. One method was "red legged hermits" (Dardanus Megistos sp???). You were kind enough to answer my previous question. One more if I may. Can't seem to find anybody that has used them. LFS can't give me any information on that type of hermit. Do you know of any place to get these guys? Is there a common name I could use? I have a 125 FOWLR and a DSB with lots of in-fauna up for about 9 months. Just got my first Aiptasia on a new piece of rock. (Came out after a couple of weeks). Any help would be greatly appreciated. Jeff <I would not worry about obtaining biological predators for just one Aiptasia. I have used a simple method of mixing up some Kalkwasser water and slowly squirting it onto the Aiptasia. It does not work all of the time, but with only one anemone I would give it a try first. It is easy to repeat/redose a few times before it is eradicated. There are also suggestions for use of vinegar and hypo/hyper salinity injections. -Steven Pro>

Turbo snail vs. hermit crab Hello! <Hi-ho!> I'm going to my LFS tomorrow to get some more snails to help with some algae cleaning, and I was reading some aquarium sites that said blue-legged hermit crabs (of which I have 3) can kill and eat some snails. <very unlikely... usually it is another species in the same shell and mistaken... read about it often in the archives if I recall correctly> I had added the 3 hermit crabs along with 3 turbo snails over 5 months ago. Two of the turbo snails inexplicably "disappeared" shortly after...I assume the crabs ate them since now the largest crab is living in a snail shell :) <could have scavenged them just the same> My question is: Can I do anything to "protect" the new snails I'll be getting? <sure... examine them closely to screen for green/brown crab species in the same shells... also provide extra and larger shells for them to grow into to prevent muggings> I'm assuming the larger the snail, the less likely to be eaten? <nope> I'll probably get turbo snails (b/c that's what the LFS usually has) but would you recommend any other species for general algae cleanup? <Astrea are better at brown algae (diatoms) while Turban sp eat green micro well> Thanks! ---Stella <quite welcome. Anthony>

Hermit Crab Killer?? Hi Everyone at WWM. <howdy partner> Thanks for all the great info on your site. It's been extremely helpful. <pleased and our pleasure!> Yesterday I discovered the remains of one of my smaller blue legged hermit crab. The tail end of his body had been removed. My question is this, who is capable of doing this? Here's my stock list in my 50 gallon; 2 clowns, 1 peppermint shrimp, 1 emerald crab (1 inch), 1 unidentified hitchhiker crab, body size about the size of a penny, now 11 blue hermits, some two to three times bigger than the one that got eaten, 1 brownish red hermit, and 8 turbo snails. The unidentified crab is brownish red, very fast, very shy and hides in my live rock. <the other hermit crab species and especially the unidentified crab species are strong candidates. But even a lack of extra shells in the tank would make like species competitive candidates as well. Most crabs are opportunistic omnivores... they are not above cannibalism> All I've ever seen him eating is algae, any ideas? Should I remove the crab regardless if it was not the culprit? <if you ever want to keep soft invertebrates in this tank, it would be best to remove the unknown crab to a fish only system... even then it like most crabs may catch and kill slow fish> Thanks Barry <best regards, Anthony>

Mysterious death of hermit crabs dear bob, <Anthony Calfo in your service> I just your web site. and you seem very knowledgeable about hermit crabs. I had 3 of them for over 3 years. last week I lost 1 of them and then yesterday I lost another one . I am very concerned about the remaining one. what could be the reason of their sudden demise? their habitat was a fish tank with small smooth pebbles, a climbing limb and were fed crab pellets and water. outside the shell they measured 2 1/2 ". I had put few bigger shells hoping that they would change their homes in them, last year, but they did not change homes. please let me know what else I can do to save the last one. <have they been misted or dunked briefly in water daily? They needs humidity to breathe easily. A change in household humidity (to drier) can have a negative impact> Can it be that the diet is poor? <if they have only eaten pellets without any supplementation, possibly a dietary deficiency> is there some bacteria flourishing and killing them? <unlikely> can I bring a smaller one to keep it company? <not recommended until you determine the problem> please advise. thank you -Hermie <do review the archives on diet for crabs... another possibility is simply age. We have no idea how old the crabs were when you bought them and three years is not too shabby. Do consider humidity, tank temp (air conditioning new or stronger and drier now?), diet, etc. Best regards, Anthony>

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