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FAQs about Hermit Crab Stocking/Selection

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

Related FAQs: Hermit Crabs 1Hermit Crabs 2, Hermit Crabs 3, Hermit ID, Hermit Behavior, Hermit Compatibility, 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,
Land Hermit Crabs, Squat LobstersMicro-Crustaceans, Amphipods, Copepods, Mysids, Hermit Crabs, Shrimps, Cleaner Shrimps, Banded Coral Shrimp, Mantis Shrimp, Anemone Eating ShrimpMarine Scavengers Crustacean Identification, Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction,

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>

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>

Blenny & Hermit Crab Compatibility, in sm. SW   8/28/12
Hello WetWeb ,
I have a six gallon tank that is about 4 1/2 years old, stocked with about 4 pounds of live rock, Xenia, Halimeda, a little hair alga and some other soft algae growing from the live rock. Not the most exciting tank so I'd like to spruce it up and add a couple twin spot blennies (Ecsenius bimaculatus)
<May fight here>
along with one or two hermit crabs (C. digueti). Would the crabs likely leave the blennies alone - assuming the fish are healthy?
<Mmm, yes>

 (Or maybe I should ask, are these blennies fast enough to get away from digueti hermit crabs?)
Also the details written on the blennies from the vendor I plan to get them from says that its okay to keep the blennies in "numbers" as long as they are introduced at the same time. What do you think about this?
<A gamble... in the wild members of this species, this genus are found either solitarily (more so when young, small) or in groups... but one can see that not just any individuals drift to/fro into others territory>
Do these fish generally do better in groups or by themselves in a nano tank?
<I'd keep singly; or at least have a contingency plan to separate>
Thank you,
<Welcome. Bob Fenner>

Clibanarius antillensis? Sel.     5/1/12
Good evening, crew.
I have what I'm pretty sure is a Clibanarius antillensis hermit crab. I don't have a lot of other creatures yet (some snails and a few blue-legged hermits), and he hasn't murdered anything that I've seen (so far), but is he likely to stay peaceful or do you think should I take him back and return him for the blue-legged hermit he was supposed to be?
<Up to you... I don't endorse the use of hermits for aquarium use period.

See WWM re>
Thanks so much,
<Welcome. Bob Fenner>
Re: Clibanarius antillensis? 5/2/12

Thanks, Bob. And hmmm.
<Welcome. B>

Stocking around Clibanarius vittatus -- 9/27/10
Hi, WWM crew!
<Hi Jeff, Lynn here today!>
This past April my neighbor gave me two hermit crabs (C. vittatus) that she accidentally brought home from a trip to Florida.
<It happens. These hermits can survive out of water for several days, so it's not all that unusual for a shell collector to accidentally bring one home. One thing of note regarding this species is that they can get fairly large.>
I happily took them, and quickly set up a 5 gallon acrylic hexagonal tank for them,
<Heeeee! Remember in the movie Jaws when Chief Brody told Quint 'You're going to need a bigger boat.'? Well, you're going to need a bigger tank!>
..complete with sand and a couple pieces of live rock (I'm hoping to get more soon). The tank also has a number of majano anemones that I purposely added to make it look a bit more exciting.
<They can be very pretty.>
The filter is an HOB that does about 100gph, and the light is a CFL that screws into its socket; I believe I have about 2 wpg. I have a couple questions about stocking and tank size. How big exactly do these crabs get?
<Big, with carapaces reportedly up to 6' (~15cm) across.>
I was under the impression that they only reached about 7cm or so, but I read recently that they can reach 10-15cm.
<Yep, and the larger they get, the more their appetite, need for larger shells, and tendency to knock things about, increases. One thing I'm unsure of is how long it takes for these hermits to attain such a large size. I imagine it would take more than just a couple of years.>
Would it be wise to upgrade to a 10 gallon setup if I plan to add other animals to the tank?
<Yes, bigger is better when it comes to keeping water parameters stable and livestock healthy, so I'd recommend going as big as you can afford.>
If I upgrade, I will be using a hood made for 2 incandescent bulbs, and will be using 2 Coralife mini CFL 50/50 bulbs (http://www.petsmart.com/product/index.jsp?productId=2753932&lmdn=Product+Type). If I don't upgrade, I will use only one of these 50/50 bulbs. (I am doing this with my anemones, and possibly any other sessile inverts that I buy, in mind.)
<Okay, just be sure to keep the hermits well fed with a variety of sinking pellets, and/or meaty bits of marine origin like shrimp, clam, fish, squid, etc.. This will help deter the hermits from preying on some of those sessile inverts (particularly any small bivalves), resting fishes or snails.>
I am asking this because I have heard that hermits can be aggressive and opportunistic and may attack small sleeping fish,
<Yep, there's no telling what a hungry hermit will pick at or try to grab.>
..and I plan to add a small damsel
<Personally, I wouldn't add a Damsel to any system smaller than 20 gallons. They're active swimmers that can be pretty feisty on the best of days, much less when they're confined.>
..and goby,
<Gobies are great. Again, just be sure to keep those hermits well fed.>
..as well as some snails and a serpent star, without the crabs harming them.
<I'd hold off on the serpent star until you have a larger system.>
Thanks very much for your time,
<You're very welcome.>
<Take care, Lynn Z>

Hermit crabs, wild-collection, BP  8/9/10
I'm vacationing at Daulphin Island and there are tons of hermit crabs, large crabs, and sting rays in shallow waters. Are they escaping the oil?
Would it be wise to take home some of the hermit crabs or would it be best to leave them?
<The crabs and sting rays you see are most likely being pushed your way by oil-tainted waters. It's best to leave them be. I'm not sure of the legality of the matter.>
<Scott T.>

Dardanus megistos, shopping in Riverside, CA...  -- 4/11/10
Years ago I bought a small Dardanus and was not familiar with the species. Well, it grew and grew and gave me many hours of pleasure watching its antics. Hermie lived for about a year and died quite huge. I would now like to obtain another Dardanus , but to obtain one on the Internet means paying about four times the price of the crab in overnight shipping charges. Not a smart investment.
I live out in the Riverside, California boondocks, Homeland, California, which is between Perris and Hemet, where an adequate tropical fish store does not exist, or, if it does, I cannot find it. There used to be three in my vicinity, but all three have gone out of business.
Where, in my area, can I obtain a Dardanus , without driving fifty miles?
<I do not know... Do you have any scheduled trips into the greater Los Angeles area? There are many shops there that stock various Hermit Crab species... I would "let my fingers do the walking", i.e., call in the ones you intend to visit ahead of time, to see if they have one of these "bruisers" in stock. Bob Fenner>
Re: Dardanus   -- 4/11/10
Thanks for the advice Bob, but wouldn't a trip into the greater Los Angeles area be that fifty miles I'm trying to avoid?
<Perhaps Craig's List? B>

Hijacked crabs 07/14/09
While on vacation at the Gulf Coast, I brought home some shells. Now I have read your comments about others doing this and I completely agree that you should not bring these home. I did not want them. I checked the shells, apparently not well enough, and thought they were empty. I left behind some really cool looking shells because they were occupied. I had collected some sand to keep my shells in, for aesthetic purposes, and put it all in a Tupperware container and wrapped that in a plastic bag. I had collected these on a Friday morning and but them in the container right away, not knowing of my little friends hiding inside. They were in the car and heat of Texas Friday & Saturday. The container was then put in a plastic bag so I wouldn't spill the sand during my flight home to Boston on Sunday. Needless to say, when I took the container out of my bag, I noticed the shells moving. I was very surprised & upset to find 3 crabs.
I put them into a larger container with some water and put some lettuce in.
Wasn't sure what to give them since I have never in my life had a crab. I am feeling very guilty so bringing these shells home and will never do it again, lesson learned. 2 of them have already died and I am afraid the largest of the 3 will go soon. I don't want to kill it. I feel like I have already murdered the other 2 just by taking the shells.
<I do sympathize with your sentiment, but you might not feel so bad if you knew... millions of snails an crabs are killed routinely for their shells, to be sold at tourist shops. People buy these shells and ornaments all the time without giving it a second thought. The fact is that we kill animals for their parts all the time... be it cows for leather purses and shoes or inverts for shell and/or pearl necklaces. You might feel bad because, this time, you directly had a hand in the animals' deaths. But when you get down to it, you haven't done anything here you haven't likely done (or supported) indirectly many times in the past. Even when you buy cotton clothes... how many animals were killed to clear the field where that cotton was grown? I'm not saying any of this to make you feel guilty.
Quite the contrary, I'm trying to help you put these hermit crabs lives, and what you've done, in perspective. Directly or indirectly, we kill animals for our needs, wants and vanities all the time. You could become a vegan, live in a mud shack and pray no more animal lives are taken for your sake ever again... but you'd likely fail even then. One day, while foraging for fruits and nuts, you might pick an apple, bite into it and discover that your teeth have severed an innocent worm or caterpillar. We can (and probably should) try to live our lives to minimize our impact on animal life and the environment in general. However, quite frankly, you likely killed more bugs on the windshield of your car on the drive up from the beach than you have hermit crabs you brought up from the beach.>
Is there something I can do to try to keep the 3rd one going without spending a lot of money?
<Not likely. You could set up an aquarium system for it. But by the time you had it ready, the animal might likely have passed on by then. If I were you, I would simply take a moment to pay your respects to the animal(s) and thank them for their sacrifice. Cherish their shells for the enormous gifts they are.>
I don't want to invest in a tank, filter, heater, and such to have it die on me. I am not planning on getting crabs or anything that might use such items in the future.
<Again, my advice... respectfully thank the animal, then end its life as humanely as possible.>
<De nada,
Sara M.>
Re: Hijacked crabs
Thank you. I understand and appreciate all your advice.
My pleasure - Sara M.

Question (please answer) A Long Way From Home - 7/23/08 Hermit crabs collected... Hi. <Hello> I have three large hermit crabs (2 1/2"- 3") and two smaller hermit crabs (1/2") that my family brought home from Galveston. <This story never ends well...> We were staying by the ocean, and found them in tide pools. I have no idea the species, what they should eat, or what to do. <Then pray tell, why did you think you could keep them? These are living things, not curio souvenirs!> We have set up a small tank, with land and water (we brought water from the ocean). <Only 'need' water, most likely> I regret bringing them now that one has died, but it is too late and too far to return to that beach. We live closer to the "middle" of the country, and can't return them to any beach. Not that I would put them in a colder sea, anyway. <So you're saying you would feel qualms about putting these crabs in a foreign environment, but had no reservations about trying to keep them yourself, despite no idea how? I don't intend to me mean, but the lack of foresight is stunning.> The water where they naturally lived was warm. Should I try to maintain that? <If I put you in a bubble, would you want me to emulate our environment, or is one with cyanide instead of nitrogen okay?> How can I recreate their sea home? I cannot seem to find anything they eat. It stays there for days and eventually I just have to re-clean the tank. What would they eat in Galveston, anyway? What species is it (most likely)? We have natural shells, some seaweed, and one odd plant on a shell (not identified, but we are trying). We originally thought they would do well with our other hermit crabs, but our other hermit crabs are land crabs, and these are in the water almost all the time. One of the larger marine crabs are almost always on land. Should I be worried? Also, if the smaller crabs are always climbing on the larger crabs, should I make a smaller tank for just the small ones? The larger ones sometimes claw at the small ones. <Gina, you're going to need to set up a small heated, filtered saltwater aquarium for these crabs. Read how through the search feature on www.wetwebmedia.com. These crabs will need to be fed fine bits of food of meaty origin, fish, squid, shrimp, etc. In the future, please try to let mother nature take care of her living things, unless you are already equipped to give back at least some modicum of what you take from them by removing them from their original home> Thanks, please answer as soon as you can, Gina & family <Benjamin>

About my hermit crabs... and no-no's re nanos... maint.    5/28/06 Hi, guys, I have spent all evening reading your very interesting site. It has already  answered many of my questions about hermit crabs.  But I would like, if possible, to have a straight answer to the following questions:   <Okay> How many hermit crabs do I need for a 24 Nano tank with about 15 pounds of live rock?   <Need? None, zero, zip> I have about 13 hermit crabs, 3 snails, and a emerald crab. <Watch this last... can become an "eater upper"...> At the beginning they did an excellent job and cleaned all of my rocks in about a week.  My rocks looked superb with beautiful violet and green colorations.  But they seem not to be cleaning them as much.  Many times I do not even see them.  They spend many hours hidden in the rocks! Therefore, the rocks are being covered with red and brown hairy algae which seems impossible to get rid of despite my weekly changes of water, an installation of another power head and reduction of the hours of light from 12 to 9 hours per day. Why are they so shy and disinterested in cleaning the rocks? <Mmm, very likely there has been a "natural" shift in the make-up/preponderance of the algae types/species/groups here... from the more tasty "red and greens" to the less-palatable browns and BGA... and also probable, a shift in food/feeding preference to excess food from scavenging.> Besides the cleaning crew I have two blue Chromis and a rose bulb anemone with its beautiful clown fish. Jeanette <... dangerously crowded... Do be "religious" re water quality testing, water changes... Bob Fenner>

Coldwater Hermit Crabs in a tropical arrangement? 10/31/05 Hello WWM Crew, I have a 25 gallon SW tank. Currently the tank is set at 78 degrees. I was wondering if a coldwater hermit crab species could live in my tank. I live in Monterey, California where there are many local tidepools that are occupied by many hermit crabs. I've looked online and the hermit crab species is Pagurus samuelis. I figured that since they are tide pool dwelling animals they are acclimated to frequent changes in their habitat,  <Good point> such as temperature, so they may be able to be ok at 78 degrees. What is your opinion? Thanks, Taylor. <Might adjust... if tried/introduced during the warmer time of the year... but don't think these will live well or long kept in a tropical setting. Bob Fenner> 

Pylopagurus holthuisi, Marine Hermits  10/21/05 Hey Guys, <Hi Tate.> I have been looking all over the web and I cannot identify what type of Hermit Crab I have. <Lets see what you have here…>I don't currently have any pics of my own, but I did manage to find two on ReefCentral pics: http://reefcentral.com/gallery/showphoto.php?photo=67809&papass=&sort=1&thecat=999 http://reefcentral.com/gallery/showphoto.php?photo=3052&papass=&sort=1&thecat=999 <He looks like Pylopagurus Holthuisi to me common name: striped hermits or red striped hermit.> In case the pics don't work he is a large green hermit with white stripes running vertically down his legs. <They work.>  It is very peaceful and eats a ton of algae. I got him when I first started and did not know any better, but I really like it and want another one to go with him in a 180 gallon reef tank. Any information would be useful.
<The crab itself is quite hardy, usually an incidental acquisition when purchasing other smaller "reef" hermits. They can grow quite large, in fact I have a specimen who currently inhabits a 6" shell. He was a fine reef citizen but as he got bigger began to topple sessile inverts and prey on other crustaceans and mollusks. I would keep a close eye on him and provide plenty of extra shells.> Thank you, Tate <No problem, Adam J.>

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.>

Taking hermits from the ocean - 8/23/04 I brought home a few wild hermit crabs from Monterey Bay, Ca <I work at the Monterey Bay Aquarium> of the tide pool variety. <Know these well> Only after some research did I find out that they are different from land types and require far more special care. <Oh yeah!!! I would suggest always doing your research before taking on any animal (even those purchased from a store)> PLEASE help, I'm desperate to keep them alive. <Not likely possible in the long term. They require a cooler temperature. They require lots of varied foods. Typically, being that they are found in tide pools, they can handle extreme variations throughout the day. But let me add that they also become stabilized with the changing tide. So they do not typically spend the entire lifespan in the tide pool. They can venture back into shallow areas or different tide pools to find better suitable foods and habitat. Your environment just won't be conducive to their ability to move to a different environment when they want. So it is highly recommended that you release back to a tide pool near if you can. Sorry for the bad news, but I just can't think of anyway to keep these alive in a home aquarium without ambient bay temps (56-68 degrees) proper Monterey Bay alga to start> We are willing to furnish them with aquarium and whatever else is needed. How about a 200 dollar to a 10000 dollar chiller just to start?> Shells are at most 3/4 inch wide, and they have very dark blue or very dark brown appendages with red antennae. We'd like help dealing with specifically this type of hermit crab, as in how many crab tank volume. As for right now, what should I do immediately? Water is low, so how should I prepare more (salinity, chemical, temperature, aeration etc.)? <Start with our website under the Marine Aquarium heading. There are lots that applies here. Honestly Oliver, I would let these guys go, then start a tank with your newfound knowledge from this site and the many other sites and books out there, then, either try again, or maybe try some tropical hermit crabs that are kept at warmer temperature. (much easier and cheaper in my opinion, and in some cases even more interesting and colorful) On the short term, how can I keep them alive? <Just too big of a topic to cover. You can read through our site on setting up a salt water aquarium. Start here: http://www.wetwebmedia.com/marine/setup/index.htm and here: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm choose all the topics that apply to you. They look fine and healthy for now, but I doubt they'd stay that way for long. <Agreed. I feel the best way to handle this situation is to leave the marine life in the tide pools for others to see. Buy only corals and fish responsibly caught, and better yet, farmed varieties. Sorry not be of more help but this is a big topic to cover. Thanks for the question. ~Paul> Thanks, Oliver

How Many Hermits? (1/8/2004) Howdy guys :)  I was wondering what you felt was the correct stocking density for hermit crabs, as I am reading all sorts of different opinions everywhere. <A strong indicator that there is no "correct" stocking density. The more different opinions there are on a subject, the more likely that any given opinion is incorrect.> I have seen ratios from 1 per gallon to 1 per 10 gallons, and I'm wondering what you guys feel is a good general rule for stocking these critters. <Personally, I use a ratio of zero per gallon. I'm not really into them--sometimes they eat things you don't want them to. I use other things (Nassarius, Turbo, Nerites, & Cerith snails and brittle stars.) As for hermit "ratios," I find it interesting that the highest recommended numbers come from those who are selling them. Bear in mind that none of these "clean-up crews" are a substitute for proper tank management. Go with what seems to make sense to you. I'd keep it on the lower end of the range if I were you.> Thank you kindly. <You're welcome. Steve Allen>
More Hermit Stocking Questions.. II
>Just so you know, I was able to pry the murderous crab (we've named him Saddam) >>Oh my God!!  Thank you for the laugh!! >..off of the two smaller crabs before limbs were torn, so they're still alive and cruisin' the tank. Every crab in the main tank appears to want to live in harmony. >>Thank goodness, good riddance, and thank goodness!  Lesson learned.  Addition number one to the "derelict tank", eh? >I've heard of cannibalistic turbo snails. I've added two more large ones to our tank (we had one in there already) and one hung out with ours for a day in the corner of the tank. When the new one moved away from the existing one, I noticed that the new one had blown white stuff onto the existing one's shell and the live rock next to him. Looked like something a pigeon would drop on a sidewalk, if you know what I mean. Excrement or eggs? >>Hhmm.. sounds like milt to me (fish sperm/semen), but I certainly could be wrong.  I doubt it's excrement.. but again, I could be wrong.  Let's hope it means that they "really like each other". >Shall I assume that since the existing snail is still intact that the new ones (or at least the one that hung out with him) have no plans to hurt him?  Barb >>I'd watch and see what transpires.  You'll know soon enough if there's a problem.  However, again, if you're really worried about it, toss him in with Saddam.  If he is a problem, maybe we can call him "Uday".  Marina

More Hermit Stocking Questions.. The Prey of Saddam! >Haaa! Thank YOU for the laugh. >>Hi Barb, you're welcome.  I always say, if you can be NOTHING else in life, be an entertainment value.   >All three of the snails are doing fine, though there's more of that white talc-like stuff on the rocks. >>Good.. I think.  Hhmm.. snail milt?  No.. I hope if someone's hip to what this is they chime in. >They don't mess with each other at all. Just passing each other from rock to rock, wall to wall. >>They just keep on truckin'. >Found an empty crab shell (not one of the extras I had added) right after I wrote you about no casualties. Apparently, I wrote too soon. >>An empty shell could be a molt. >Glad Saddam's in solitary.   >>So are WE! >Happy New Year, by the way. I hope 2004 is good to you and those close to you.   Barb >>Thank you, Barb.  Likewise, and let's hope things continue going (relatively) smoothly with your tank.  Marina

More Hermit Stocking Questions.. The Prey of Saddam! II >Thanks, Marina. >>Much welcome, Barb. >Regarding the possibility of the empty crab shell being a molt, wouldn't I see a new occupant of one of the spare shells (that are deliberately different looking than the ones they came in)?  Barb >>Not at all.  Just because the crab molted doesn't mean it didn't like its current digs, it just needed to shed.  Sometimes it can be hard to tell whether or not there's actually a body in there, I've found giving it a squeeze usually settles the question (though, after a few days it's going to be same same).  Marina

Empty Shell Syndrome? >Well, that shell looks pretty empty and it hasn't budged from its current position since we ousted Saddam over a week ago. No sign of an empty (or full) exoskeleton, either.  :(  Barb >>We should let Saddam's people try him and decide what should be done. }:->  Marina

Cleaning Crew Hello WWM crew. <Scott F. on the WWM "cleanup crew" tonight> I'm currently looking into getting a cleaning crew for my 180 gallon aquarium that consists of 200 lbs of live rock and 300 lbs of sugar size aragonite and wanted to see what you recommended in terms of crabs and snails, I've been hearing some negative things regarding the blue legged hermit crabs and Astrea snails. Thanks, Jose <Well, there are many possibilities here. I have, and still do, use the supposedly "reef safe" crabs without incident. However, keep in mind that even the "safe" species are, to a certain extent, predatory. They can and do occasionally nibble on your desirable corals, and sometimes, your snails! A lot of times, the "bad guy" types of crabs sneak into your tank by using the same shells as the "good guys" inhabit. This may be why a lot of people give a "bad rap" to the supposedly "reef safe" hermits (and another reason to quarantine/inspect all new arrivals!)! I have had great luck with Trochus, Strombus, Turbo, and Nerites snails myself, and would definitely recommend them as part of your "crew". Also, brittle stars (almost all of them) make great scavengers and detritivores, and you can stock them at the rate of about 1 for every 20 gallons. Just use common sense when selecting your cleanup "crew", and you should be okay. Many retailers offer "packages" of these animals, so you should have no trouble locating them. Have fun and good luck!>

Hermit crabs - algae Dear WWM: If you were to choose 5 species of hermit crab or crabs in general, for routine cleanup of green hair and filamentous algae in my reef tank, which would they be? I intend on having corals and want "reef safe" varieties. I live in Ft. Lauderdale and can collect hermits from the tide pools.  Can I use these?  If so, what species...blue legged, red legged, etc Thanks, Steve < I would do mainly red leg hermits.  Sally Lightfoots are good at eating hair algae also. Cody>

Hermit Crab Hi y'all... Are there any types of hermit crabs one can not put in their tank with corals? A friend went to the ocean on vacation and when they got home discovered one of the shells they picked up still had a tenant and they asked if I wanted it knowing I had a marine tank. I don't want to see the thing die and it's 11 hours to the nearest ocean.
<I would not introduce this hermit to your aquarium, especially with corals. Hermit crabs in my opinion tend to be very destructive creatures and are not trustworthy in a reef type setting, Good luck, IanB> Thanks

How many hermits - 10/14/03      I'm a little confused. <Aren't we all?>  On the hermit crabs page, it says: "If you use them, place about one, two small Hermits per actual gallon of your system. <Emphasis on small> Use a mix of species and make sure and provide many "upgrade" homes (empty shells) for your Hermits to move to." <I can agree to this view with the exception that the hermits should be small>      However, on the first hermit crabs FAQ page, the first question reads: "Snail & Hermit Crab waste Hi Bob: My tank finally cycled with a lot of algae bloom. Two days ago I added 10 Scarlet Reef Hermits 10 Turbo/Margarita Snails and 30 Red Leg/Left-Handed Hermits from FFExpress. They have done an excellent job cleaning but I noticed a lot of waste since I added them in the tank. Is this bad for the tank? And should I pull out some of the hermit crabs out? <You neglect to mention how large your tank is. I would not use anymore than 1 hermit crab per 10 gallons. I use about 1 snail per 2-4 gallons depending on the tank, lights, etc.> Thank You, Aram <You are welcome. -Steven Pro>"      So which one is it? <Well, I can see this view as well, different strokes for different folks. Let me tell you what I have in my ten gallon tank. Two hermits. That's right....two. Ask me how many I started with? Ten hermits of varying species. Aggression and starvation has eliminated the competition. So my recommendation is one no more than two per ten gallons period. The same equation works in my twenty gallon for the most part. I now have three left out of twenty. So maybe no more than four in a twenty gallon should suffice>  There's a big difference between one or two hermits per gallon, and one hermit per ten gallons. <Agreed. The above recommendation is what works for me. You might have luck with a few more if you feed them regularly. Is it a little bit more clear? Hopefully so>      As you can see, I am confused. <Naw.......just a difference in point of view. You are gathering information for a better point of view. Good on ya' mate, -Paul>      Brian

The Chromis Were the Culprits? V - Hermie Question >You're a woman of many talents, Marina. Thanks so much. >>Aw.. shucks, thank you Barb. >The very best holiday wishes to you as well! By the way, everyone is getting along swimmingly (sorry, couldn't resist) in the main tank. >>Am I rubbing off?  I love it.  ;) >No more turf issues either. >>Excellent! >I've got a crab question for you. I currently have one small hermit crab (green legged with red horizontal striping, red antennae) and one nickel-sized emerald green crab. >>Watch out for those Mithrax (emerald) crabs.  They are known to become quite destructive.  However, don't can the crab just yet, but DO watch him.  Plenty of folks have had theirs for years with no problems. >I'd like to get another 20 hermit crabs (110 gal tank), but I want to make sure they're compatible with the other two crabs (and the 1.25" dia Turbo snail). I've read a lot about hermit crabs and it seems that the blue legged and red/white/blue legged species are the most non-aggressive. What is your opinion? >>Agreed, the very slender/delicate types seem to be the most well-behaved in general.  One thing to remember is that any Hermie will quarrel with another if they both want the same flat.  So, do provide plenty of extra shells. >Also, do I need to quarantine the new crabs before dropping them  (and a bunch of empty shells) into the main tank?  Barb >>Most folks would say no, and honestly, I probably wouldn't bother for my own tank.  However, if it were for a customer's tank, I would q/t them.  Kind of like when you take care of other people's kids?  I think you'll be fine, if you're worried about the shells then boil them for 10-15 minutes to make sure they're clean.  Drip acclimation will be best for the hermits, I'm sure you've got THAT bit down by now.  Honestly, I think you and they will be fine, though you might be feeling a little gun shy and want to q/t to be safe.  Marina

More Hermit Stocking Questions.. >Thanks, again, Marina. >>My pleasure, Barb! >When you say two dozen "animals", are you just talking about the invertebrates (in this case hermit crabs) or are you referring to ALL of the tank inhabitants (i.e., including fish)? >>I am referring SPECIFICALLY to total hermit crabs.  I feel that Steven Pro's assessment of stocking is quite prudent, and you would do well to follow that advice. >Regardless, I bought 10 dwarf red legged hermits today at a LFS (none around here had any dwarf blue leg or dwarf zebra in stock and Live Aquaria charges $25 for s/h) and put them into the main tank after adjusting them to its temperature. >>Salinity is another VERY important parameter to measure and adjust for, as well as pH (this is more for the people who read the FAQs daily). >Unfortunately, my much larger dwarf red leg hunted two of them down and grabbed hold of them (one at a time). >>Ouch!  Son of a GUN!   >No matter how many times I relocated the larger one to high live rock or different areas of the tank, he was relentless...and FAST. >>Argh!  Is he a candidate for the "derelict tank"?  (These seem to be growing in popularity, and they often seem to do MUCH better than the more dedicated setups!  Go figure.) >Their shells were so much smaller than his, I doubt that housing was the issue here. >>Absolutely agreed.  But, don't tell me he didn't even EAT them. >I decided to put the big bully into the QT (scrubbed clean, new bio-wheel, perfect water conditions due to the use of a good deal of the water from the main tank). He was originally one of four that we purchased early in the year... a murderer who apparently didn't kill for shells, but for sport! Let's see how he likes solitary confinement! >>Oh lord, I bet he DOES like it.. >If your reference to "animals" was just to crabs, then a few more of another species is surely in order, to prevent brawls.  Barb >>Agreed.  Did I mention that I have a friend who buys shells at the craft shops?  She boils them for a while, then just tosses them into the tank.  I know other folks who go scrounging the fish shops and ask for the "dead snail shells", which the shops tend to just give away.  I'm very glad that things are going relatively smoothly (murderous hermit crabs aside, of course).  Marina

More Hermit Questions - Salt System >Thanks, Marina, and Merry Christmas. >>Thank you, Barb.  I hope yours went well. >I haven't had any success in finding quantities of hermit crabs at LFSs, so I'm planning to venture into an online purchase through Live Aquaria. Any concerns? >>This outfit has a very good reputation. >They have a 10-day conditional guarantee where you must quarantine them or they take no responsibility for them. >>This is prudent on everyone's part. >By "drip acclimation", do you mean float the transit bag, add 1/2 cup QT water every 10 minutes or so 4X, then add to the tank? (Live Aquaria suggests 4-minute increments and dumping half of the bagged water after the last 1/2 cup addition, adding tank water, netting the livestock (even inverts) and only adding THEM to the QT, not the bag water. They recommend quarantining for two weeks.) >>Two weeks is rather insufficient, in my own opinion.  A drip acclimation method is one where you actually set up a "drip line", made with a length of airline tubing and a valve to control the drip rate.  You then set up the animals in a container (in the trade usually a flat, but sufficiently deep, plastic pan or box - think cat litter-type box), then create a gravity-fed drip.  There are a couple of ways to do this, one where you'll have to change out part of the water on a regular basis to ensure removal of all shipping water, the other where you have one drip of new system water going in, and one from the acclimation container going out (this will be set up so the drip rates are equal and constant, leaving a constant water level as well).  This is, in my opinion, an safer method of acclimating invertebrates.  However, many folks have neither the materials, money, nor inclination to go to this trouble, in which case the method outlined by LiveAquaria should be fine. >Do you think 12 each of dwarf red tip hermit, dwarf blue leg hermit, and dwarf zebra hermit, and one scarlet reef hermit is too much for the 110 gal tank (holding about 50-60 lbs of rock)? >>Yes, I do think that's rather much.  I'd go with no more than two dozen animals in a system your size, and honestly, since I feel it's easier to add more if necessary (plus, allowing for other animals that would make use of detritus - such as Ophioderma spp. - would give additional leeway), or you may end up needing to feed supplementally. >I was planning to put 24 empty shells in there with them. Better to put in 36 empties? What do you know about the behavior of dwarf zebra hermits?   >>Don't know any particular specifics, you want to give them each at least one extra shell that's just a bit larger than their current digs.  Lots of folks will actually go match shells from craft stores (cheaper!).  Shape is important.. I think I've mentioned this before though, yeah? >P.S. to my reply earlier this evening - My Mithrax doesn't bother anyone/anything in the tank and prefers to hang out underneath things. >>Yes, they do prefer the underhangs. >Even when he does climb, he's very unobtrusive. Overall, a pretty shy little guy who keeps to himself. >>As long as he keeps to himself, it's all good. >The longest I've seen him out and about is when the Tang's seaweed clip falls off the glass on occasion and he runs over to pick the remaining clipped morsels out as a snack.    Post postscript to my first reply this evening - I just read Steven Pro's response to an FAQ on your site regarding quantities of hermit crabs. He recommended no more than 1 hermit per 10 gallons, so it looks like I'm better off just getting another 9. Maybe a mixture of dwarf zebra, dwarf blue, and dwarf red tip (leg). Your thoughts?  Barb >>That number sounds MUCH more like it, and I think an even mix of the three species will reduce quarrels over housing.  Marina

I am just getting started I am just starting out in the reef aquarium game and I hope you may have suggestions on the clean up crew. How many Florida snail per gallon of water? How many blue leg Hermit crabs per gallon? Can you have to many of either? I have a good protein skimmer, yet I want to ensure a clean tank. Also, is there a rule of thumb when it comes to number of fish per gallon, or inches of fish per gallon, of water. Thank you, Mike E >> Don't know that I'm a good candidate for asking this question... Am not as big a fan of these organisms for the intended purpose... as many, most other folks. For me, one or two per real gallon (take out displacement by other materials in the tank) is the most I would place... Not to be mysterious, or appear that way, my misgivings about snails, hermits have to do with their utility, their propensity to "snack" on other desired livestock, their roles as transmitters of disease and pest organisms, their mysterious death/pollution incidences... And the better choice of other organisms as helpers, proper set-up and maintenance... If a tank is big enough... there are fishes, other invertebrates that are more appropriate for the same "jobs" people intend for snails, hermits. Bob Fenner

Hermit crabs Hi Bob, I am a new user to your forum and find that you seem to give clear, concise answers. <Thank you for this... some, some days don't seem too lucid to me...> My question regards hermit crabs. I have 25 blue and 25 red reef crabs in my 75 SW tank. I felt they were invaluable in cleaning up the mess at the later stages of curing live rock. There seems to be a big debate about the keeping of these crabs at this density. What are your thoughts on this "clean up crew"? <These animals (Hermits) can be useful in many settings... but in some circumstances, species mixes more destructive than helpful... It's not lost on me that many environments in the wild lack such life. Am more of a "fan" of a broader, many-input approach to "tank cleanliness" with adequate circulation/aeration, different types of filtration, careful stocking and feeding, use of refugiums, live macro-algae... providing other nutrient pathways, competition (chemical, predatory) and maintenance providing for "cleaning". Bob Fenner> Thanks, Tom

Clean up crew Hi Bob, Hope your morning has been good so far. System recap: 90gal, 30gal sump, Turboflotor 1000 and Aqua-C EV90 (one of these will be going to my parents' tank soon), 90lbs LR, 80lbs cc, Dolphin 800 return pump, Rio800 for add'l' circulation, 210watts pc. Well, my water parameters as of yesterday: 0 ammonia and nitrite, 10ppm nitrate, 0.4ppm phosphate, ph 8.3, temp 82F, salinity 1.022, Alk 2.2, and calcium 300ppm (will increase dosage of 2 Lil' Fishies C-balance). With those readings, less skimmate, and appearance of green hair algae, I think my rock is cycled and I would like to add my clean up crew (to ASSIST in MY periodic stirring/maintenance)!!! :-)  <And indirectly to bring down that phosphate...> I was going to start with a small Kole tang, and a dozen snails and hermits.  <Good choices> I didn't want to add anything close to the amount they offer in the standard clean up crew packages. I know you don't care for hermits much as cleaners, but of the red, blue, left-handed, etc., which would be the safest in a reef environment (stays small, not tooooo opportunistic/predacious)?  <The "blue": Clibanarius tricolor... image, more on the WWM site under Hermit Crabs.> I kind of like the look of hermits crawling around. I also wanted to add a sand sifting star (not brittle stars). I think I've seen them offered as "White Sand Stars", and they were supposedly much safer than other stars. Do you know the "correct" name for these and if they truly are safer?  <Yes, Archaster typicus. Much safer: http://wetwebmedia.com/seastars.htm> Do you acclimate the hermits/snails/stars the same as fish (dip/quarantine)? I know you have that on your site somewhere, but I couldn't find it (sooo much info available). <Should come up with the Google search tool... I don't dip these or recommend same. Do quarantine ones that look like they "may not make it"> Oh one more, I have a bunch of fuzzy, copper colored algae on my rocks. I couldn't remember if this was transient or if it was indicative of something I needed to change in my water/system? <Transient... with unfolding (aka evolution) of your system, it too will pass> If you don't feel like repeating yourself today, the appropriate links will do! :-) Thanks again for all the help. Hope my long email was more info than babble. Khoi <No worries. Bob Fenner>
Re: Clean up crew
Hi Bob, <Should come up with the Google search tool...> Hmmm, that would be a good idea! :-) No, it should read: "You should USE the Google search tool..." Yeah, I got to start making use of the available tools! It's just that I've read through the site so many times, I think I know where all the info I need is... not! You truly provide a ton of info. Thanks for the answers anyway! <Hmm, when do you want to give answering these queries a go? You're about due. Bob Fenner>

Hermit crabs hi there are a lot of hermit crabs just in the bay down from my house I was wondering if it would be alright to put them in my tank do some hermit crabs need air because these hermit crabs are always in the water when I see them but in shallow puddles because I wouldn't want to drown them or anything <You are a good observer... many hermit crabs are much more amphibious than totally aquatic. Do provide a small area for these to crawl out of the water. Bob Fenner>

Hermit Crabs Dear Bob, Thanks again for your wonderful site and the many great articles and books! I was wondering do you know of any commercial sources for Petrochirus diogenes? Or other large hermit species. I was thinking that they would make for quite a cool species tank. All I can find for sale are the smaller ones that are sold as "clean-up crews" and I am really wanting the larger ones. Thanks Again and Happy Holidays! Wally <Thank you for writing... there must be some commercial collectors/sources for these larger Hermit species... they're often numerous in the wild, not hard to catch, ship... Please send your query along to the folks at the Marine Center (http://www.themarinecenter.com/, as they're hopefully more aware if there are such suppliers. Bob Fenner>

A Question of Algae Eating Inverts Dear Robert, <You reached Steven pro today, filling in for Bob.> Thank you for answering my last question. I now have another question. I have hair algae problem, in my 29 gallon tank, can I put red legged hermits with my live rock? Will they destroy my rock? <Scarlet red reef hermit crabs are one of my favorites. They are pretty much strictly algae and detritus feeders. I have never had any problems with these, unlike the blue legged hermit crabs.> I do have a sally light foot crab and was thinking that I should put an emerald crab to help control the hair algae. I know that it is a possibility that they will fight or kill each other, but is this usually the case. <Hard to say for sure. That is why there is a difference in the articles you have read. I would probably advise against both in a 29. Less room for one to get away.> In some articles that I read says that they have different habits and don't usually bother each other. My tank has plenty of hiding places and live sand if that helps any. I do want some more inverts in my tank, what is the route that you would take in my situation. I won't hold you responsible for any decisions that I make, so please give any advice or info that you have. Thanks <I hope I have been helpful. In recap, Scarlets yes, emerald no. -Steven Pro>

Crabs Hello, back again! It's so nice to know that when I post a question, it will be answered! This service is highly needed today and I am delirious each time I get the chance to use it!. Also, that Steven, is FUNNY! When Robert was out he sure came up hilarious scenarios for his absence! <Thank you for the compliment, but I think you meant Anthony. He was the one coming up with the truly hilarious reasons for Bob's absence. I was only moderately amusing.> So I just wanted you to know, that although I may appear to be casual in my need for info, I appreciate it so much!! It makes this hobby so much more possible when you have almost instant answers! Now, to my question,..............hmmm, I forgot it! Oh yeah, last summer I went down to our local beach, (I live on Cape Cod) and collected about 20 little hermit crabs. They were taken from the small pools that form along the beach when the waves come in. Seeing that this water was always very warm, I figured they would do nicely in my reef tank. Oh contrary! It appeared they WERE settling in nicely for about the first 3 months. But then I noticed that their numbers were dwindling. I wasn't sure if they were hiding or what, but now, about 5 months later, I haven't seen a single one! All I have in my 55 g. tank is 3 dominos, 2 yellow tail blue damsels, 2 camel shrimp, and 1 coral shrimp. I don't think THEY would be eating them. Can you tell me why they would die off? Also, was it illegal to take them from the beach? I see little kids do this all the time, and I have not yet seen the "Crab Police" stop them at the gate! I really hate to pay 3 dollars a crab at my local shop when I can get them for free! <As you discovered, these little guys are a temperate species and while the water was warm at the time, these crabs needed/were use to it getting cold and their numbers dwindled when it stayed hot. You would be better off buying the tropical variety from your LFS. I prefer the so called scarlet reef hermit crab.>Thanks guys! Pam <You are welcome, Steven Pro.>

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