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FAQs about Hermit Crab Disease/Health

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,
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,

Many Fishes will eat Hermits... yes, shell and all. Cephalopholis polleni 

Can you offer advice on this issue with hermit crab; no data of use, rdg.       7/24/12
<... eight megs of pix, why?>
Image #7074 ( probably 1st image attached) is the crab when first got him from ocean near Key West.  late May.
sent you this picture at that time when we were attempting to ID him.
The next 4 images (9311, 9313, 9315,9316) are how his legs look today. 
July 23.  Am hoping this might help you
determine what you think has happened and how I can help him recover.  Legs have pale areas as you can see.
He isn't as energetic as before this began to happen.....alive, but more lethargic. No predators of any kind in tank only 1 damsel and live rock.  eating Mysis shrimp and flakes
Pls. advise best plan to prevent losing him if you can.  thanks,  Chris
<... data? On water quality mostly, foods/feeding... Read here:
and the linked files above. Bob Fenner>
The 'whitishness' has now spread up his legs and is more than just one spot as was the case in my first inquiry to you July 9.  He is still alive and moving about but certainly not with the spunk he first had....

question about crab white spot on claw     7/9/12
I would appreciate your input on something that I hope is not a serious issue with my crab.  He has developed a whitish  ( loss of color) area on his right front claw and has been rubbing the area with his other claw as though trying to remove.  Also noticed him rubbing it against the coral. It isn't something that will scrape off though. This has me quite worried. 
Do you have any ideas to offer as to what has happened / or what I can do to remedy?
<Looks under cropping, close-up view to be a mechanical injury. I'd do naught but increase by double your iodide-ate supplementations>
This is pic. of him I sent you in May. When I cleaned the tank last night I put my protein skimmer on to see if that helped anything. Water test fine.
<Need to know alkaline earth and alkalinity measures>
  I still never found a definite ID for him.
Thank you again.
<Welcome. Bob Fenner>

Hermit crab genocide/Or Starvation 5/24/12
Hello WWM Crew.
<Hello Kristen>
 I inherited a 6 gallon Nano Cube JBJ from my sister.  It is saltwater and was in bad shape with no remaining survivors when I got it in January 2012.  I did tons of water changes and added two blue leg hermit crabs two weeks latter.  Despite the tank still needing work they did fine.
Since then I have gotten the water quality under control and gradually added two scarlet leg hermits, yellow watchman goby, four Astrea snails, two bumblebee snails, an electric blue leg hermit, and two small tank raised clown fish.  I have Zoanthids, button polyps, a Duncan coral, a few mushrooms, green star polyps, candy cane coral, and pulsing xenia.
Recently I had a spike in diatoms all over the surface of the tank but the water tested fine with just a small amount of Nitrates prior to regular water change.  Around this time my largest blue leg hermit crab died and I found him hanging lifeless out of his shell.  Then a week latter my electric blue died followed a week latter by my last blue leg hermit. The diatoms are gone and the fish and corals all seem healthy except some of my button polyps have turned inside out. I took in another water sample to my LFS and all was good except the salinity was a tiny bit low, which i corrected with a water change.  This morning I discovered a dead scarlet leg leaving me with only one scarlet leg hermit crab left.  I cannot figure out why my hermits are dying but everything else is fine.  I thought hermits were the heartiest <hardiest> creatures and my two blue legs survived the
rough initial renovation period in my tank.  They have ample shells to move into of varying sizes and I feed the tank marine fish flakes daily with frozen Mysis shrimp about 2-3 times a month and an occasional piece of seaweed.  I do have a few possible theories though:
1)  The low salinity and the fact that I have not been as consistent with water changes since I started a new job working midnight shift.
I normally change a gallon of water once a week due to my tank being only six gallons and i admit, kinda overstocked.  The water never tested very bad though.
2)  The crabs all seemed paler than when I purchased them but I don't know what my calcium levels are and I added the seaweed for added keratin.
3)  I thought maybe scavenging, but I think I've ruled that out since I am left with my smallest and most docile hermit crab "Lucy".  Unless one of the other creatures is capable of killing a hermit.
<Hermit Crabs are opportunistic feeders and if food is scarce, which I believe it was/is, then they will feed on most anything including other Hermit Crabs.>
I forgot to mention I have a few accidental arrivals: a bristle worm who has grown to about 1.5 inches, and three brittle stars.
4) Lastly, I thought about temperature.  My heater is set at 74 degrees F and the tank ranges from 75 to 76 when the lights are off to 79 to 82 with the lights on.  My first hermit crab died at the same time that the external temperature in my house changed due to the weather warming up so the tank is now running warmer than it was prior to the deaths.
I love hermit crabs they are so comical (except the scarlet legs who do absolutely nothing) and would really like to replace them but I'd like to know what might have killed them all first.  Lastly for my tank how many hermits would you recommend and what kind?
<I'm quite sure they were not getting enough food.>
Thank you so much.
<You're welcome.>
 Your website is a valuable tool and a joy to read :)
<Glad you use/enjoy.  James (Salty Dog)>
Re Hermit crab genocide/Or Starvation 5/24/12

Thank you for your answer.
<You're welcome.>
 Now that I think of it I did cut back on food when the diatoms sprung up thinking they were do to overfeeding.  Then the crabs started dying.  Should I replace the dead hermits?
<Why not?  James (Salty Dog)>

Anemone Hermit Crab Falling To Pieces/Dardanus Health   4/23/2011
<Hello Liz, and sorry I took so long getting back to you.>
We had our Dardanus pedunculatus <Anemone Crab> for a little over four months. He was eating a varied diet of different prepared frozen foods, freeze dried krill, algae, and silversides. Since he had a fondness for ripping mushrooms off their frags and eating, oh, anything he could grab. We bought a 15-gallon sump for our 29-gallon tank and made it a species only habitat for him with a deep sand bed, around 7 lbs base rock, and some macroalgae. Maybe a week ago or so he started to become very lethargic and picky about what he ate: only marine sinking pellets (his favorite) and the insides of the silversides. A few days ago he began refusing all food and wouldn't move from one corner; he didn't even care to steal food from his anemones. When I looked in on him today, I noticed that around the front of his shell were all his legs. Not an exoskeleton, individual legs as if they had been ripped off one by one. I tried to convince myself it was molt, but when I flipped over his shell (really ticking off his two anemones) I could see his little eyes and face way back in his shell with no claws or legs in sight. The sump has been around for about three months, the display tank for about a year. As of this moment, crab parts still to be removed, numbers read as:
Temp: 80'¢
Salinity: 1.0255
pH: 8.0
NO2: 0.3
KH: 9
Calcium: 740 mg/L
<Yikes! Way too high.>
NH3/NH4: 0.12
<This should be zero, no more.>
CO2: 2,7
I know it's a bit warm and the calcium is out of control, but would that cause his legs to fall off?
<Based on your information, I'd say it was a molt gone bad. The high calcium may have made the exoskeleton a little tougher to get out of. Crabs do need/require iodine/dide present in their water as it aids the molting process of the animal and I'm guessing you do not dose iodine.
I suggest dosing iodine per container instructions and get the calcium level down. This will be a slow process but can be accomplished by weekly water changes with no additional calcium dosing. If the crab survives it will molt again, and this time around it should have it's legs back. You likely will have to hand feed the animal during this
time period.>
Thanks in advance for any advice you can offer.
<You're welcome. James (Salty Dog)>

invertebrates... Hydrozoan (?) control, hermit crab parasite/symbiont?    7/2/10
What's up? I love the site.
<Well okay!>
I have a question about something in my tank... I got about a pound of LR a few days after I set up my tank and I noticed this stuff on one of the small rocks; it looked like maybe a "hair algae" to me - I hadn't done any research about algae or LR at this point. I didn't think anything of it.
When I got my 2 blue-legged & 1 red-legged hermits the red-legged hermit ate it off the rock. It's pom-pom-shaped and each "strip?" has a tip like a "Hydrozoan." Which each move independently, so I know it isn't an algae, but some kind of animal. The thing is they're multiplying all over the panes of glass where the red-legged hermit can't get to them. Now after getting a tiny hint of info I've scraped them off the glass and tried sucking out as much of them as I can with a turkey baster, but is there anything else that will eat them? ...off the glass.
<Not likely, no. You may have some "luck" with time going by... their dying off for whatever reason/s. Read here:
Also, I'd like to know some advice about a boring worm in my red-legged hermit crab.. there are two, one smaller than the other. Should I try to extract them? Can you tell me how?
<Maybe, with tweezers...>
I haven't been able to find much info on the net at all, except that they eat hermit crab eggs. It's supposedly a symbiosis? How do the hermit crabs benefit from them?
<Sounds more like space "parasites"... in some classification schemes for Symbioses, there are classes of parasitism... where the symbiont gains at the expense of their hosts... Bob Fenner> 

marine hermie hanging out of shell -- 3/14/10
Hi guys,
We've had our single marine hermit crab for about 2 ½ years. He's alone in his saltwater aquarium. Has molts pretty regularly (about 4 times since we've had him) and has grown at least 2-3 inches. He eats well, is active and has seemed content in his environment. For the past few days he's been hanging outside his shell
<Not a good behavior>
sometimes just his front claws, other times nearly his whole body. Sometimes he wraps his claws around the pump tubing and kind of hangs there. I reduced his water temp a little bit, but he's still doing this. He has several other empty shells in there, but he's admittedly picky. If I make too sudden a movement he'll zoom inside his shell and he fits all the way inside. Is he sick?
Is he uncomfortable in
his shell and wanting a new one?
He did move over to a different shell
today and he's hanging outside that one too. Any thoughts?
<Need more information re water quality (Ca, Mg, Alk...), foods/feeding... Please read here: http://wetwebmedia.com/hermitdisfaqs.htm
and the linked files above... but this Hermit Crab may "just be getting olde">
Thanks in advance � you guys are the best.
Laurel Hoitsma
<Welcome. Bob Fenner>

Hermit Crab sick/losing legs  1/29/10
Help! I'm at a loss. We did a water change on our 75 gallon tank 3 days ago.
We also put a new larger shell in for our hermit crab. The hermit crab immediately moved to the larger shell and began wondering around the tank.
Later the same night, after the water change was complete, he just stayed still and won't come out of his shell. It has now been in the shell sitting in the same spot for 2 days. I picked it up out of the water tonight and it is alive but its leg fell off. We also have a very large green spot puffer, 1 damsel, and a green wolf eel. The eel has been hiding since the water change also, but the puffer and damsel act fine and are eating well. Any suggestions? Any help would be appreciated. We have had the hermit crab and eel for at least 11/2 years and hate to lose them.
Thanks!! Tara
<Hello Tara. While crustaceans can fail to moult properly because of insufficient iodine and other chemicals, and will be stressed/killed by use of copper-based medications, I'm tempted to put the cause in your case down
to its tankmates. All pufferfish view crustaceans as food; the only thing that stays their hand (beak!) is whether the crustacean is big enough to fight back. With that said, a puffer that was small 1.5 years ago may well be at a size now to view a small hermit as dinner. In addition, your wolf-eel, Congrogadus subduscens, is a confirmed crustacean-eater. Wild fish consume things like snapping shrimps and mantis shrimps, crustaceans of considerable size and firepower. A hermit crab, especially one that had just moulted, would surely be on the dinner menu. Even if the puffer and the wolf-eel haven't yet killed the hermit, they could easily have pulled off limbs while trying to overpower the crab, or simply harassed it to the degree it is too nervous to leave its shell. Cheers, Neale.>

Two quick saltwater questions 3/16/2009
I have two quick questions.
Refer to this photo:
1. Have you ever heard of algae growing on the antennae of hermit crabs?
<Mmm, yes... though I don't think this is a "normal" or healthy condition for most species>
The big zebra hermit crab has what looks like red algae on his antennae that wasn't there until recently. It runs the entire length with a bigger clump right above the eyes.
2. Do you know what type of short hair algae that is in the photo?
<Might be a Derbesia species... can you send a larger/more highly resolved image?>
It doesn't rip off the live rock easily and none of the animals (four species of hermit crab and three species of snail) eat it. The hermit crabs do think it's a nice jungle gym though.
<Heeee! Please read here: http://wetwebmedia.com/algaeconMar.htm
and the linked files above... to gain an understanding of what your options, challenges may be here>
Like me nice crop of bubble algae?!
<Keep it!>
<Welcome! Bob Fenner>

Electric blue hermit death   4/19/07 Hello to who ever answers my query, I'm not having any success with hermit crabs, I bought a scarlet hermit a month or so ago which didn't last long in my tank, after I'd put it in it was lethargic and after a few days it molted then died a few days later still in its shell. <Mmmm> I don't think I acclimatized it for long enough could this kill it a week after or is that unlikely? <The last> If that didn't kill it I'm beginning to think it may have been my salinity, it was a little low with an spg of 1.022, <Is a factor, yes... A contributing cause likely here> so after I bought an electric blue hermit which started to become lethargic too I realized that my spg should be raised after I had been reading up about how they (and other things) do better with water closer to natural sea water, <Ah, yes...> so I have been gradually raising my spg over a period of about 3 days now, but my crab started to moult and died. I'm really upset about this as I really liked him (or her?) and want to be able to keep hermit crabs as I like them very much. <Good> All my water parameters are fine Ammonia Nitrites and Nitrates are all 0, Calcium is 400, Carbonate Hardness 8.4, Ph 8.2 and always steady, temperature steady at 76 F, I use Instant ocean and carry out water changes twice weekly (5% of the tank volume) I buffer my evaporation water (which is RO water as is the water I use for the salt mix) with Bicarbonate of soda and always make sure that any evaporation losses are only added gradually using a drip which I monitor so as not to cause stress to my tank inhabitants. <Good practice> There is plenty of water movement and the tank is turned over 20X and hour with powerheads. Should I just wait until my spg is at 1.025 then try adding another hermit (slowly by the way as I did when I added the blue one!) and hope I've just been either unlucky (not as much as the poor crabs) or it was the spg, or should I just give up on them? <Up to you... the NSW (Natural Sea Water) condition/s will help... but there could be something/s else "off" here> I don't want to keep killing the poor creatures it upset me when they died (Its my birthday today too, what a day to lose a pet!) <Happy b'day to you!> I eventually want some peppermint shrimps but I'm not adding any other crustaceans until I can keep a hermit alive! <Ahh!> By the way I have a small hitchhiker crab that seems very happy in my tank he lives in a shell (not like a hermit, it uses it as a cave) and grabs food when it comes near even though I'm sure its nocturnal. <A good bio-indicator... Given that this one crustacean is fine here, I'm wondering if the larger part of the mortality of your two Hermits might be due to their initial health...> I have a common clown and a Starry Dragonet <And this animal as well is quite touchy... another indication that your system itself is in good order> which are both doing extremely well all the snails and slugs <And these as well...> etc are ok too. Thanks in advance. Faye Ps Sorry if I've rambled on a bit I've got a cold and feel a bit woozy <Mmm, I would try another "batch" or location/store source for other compatible Hermits... Ask that the ones you buy have been on hand for a week or more... And please read here: http://wetwebmedia.com/hermitdisfaqs.htm and the files linked above... to settle your mind, perhaps reveal something we're not "seeing" here. Bob Fenner>

Hermit's a tripod now???   3/11/07 I have recently noticed that one of my larger--actually the largest of my red tipped hermits has lost many of his legs.   <So the Vietnam was is raging in your tank?> He currently only has his pinchers and one left leg.  He is unable to walk or climb.  The only thing that he can do with seemingly great difficulty is turn in a circle. <This is to be expected with a Septa-plegic.>    I have been hand placing food in front of him for the past couple weeks to prevent him from starving.   <As long as he is eating it, and you can continue this, after a few molts, the crab should start to grow new legs.> All of the other hermits are fine.  -----Is it normal for this to happen to this degree?   <It is never normal for inhabitants to start losing limbs.  The Sally Lightfoot that you mention below is a likely culprit.  Actually, if you have a refugium, or another fishless tank to put this one in, I would do that.  Eventually you will be E-mailing us wondering what ate your fish.  The answer will be the Sally Lightfoot.> My water parameters are and have been in perfect or near perfect range for over a year.  I only have a couple of Damsels, Chromis,  O. Clown, Sally Lightfoot, snails, smaller hermits and corals in my tank. My biggest worry is that I am only prolonging a horrible life of  immobility!  Is it possible that he will regenerate his 3 lost legs? <Please see above.> Or have I literally made him a "sitting duck"?  Any thoughts would be greatly appreciated!! <I hope this helps, Brandon.>

Hermit disaster... Unsuitable env., reading     12/22/06 Hi All, <Andrew> I am hoping that you guys can help save my hermit crabs.  I started a saltwater tank a month ago.  It's a 65 GA tank with approximately 75 pounds of live rock (some old and some new) and some base rock, as fillers.  I tested the water last night before buying a number of hermit crabs.  The ammonia and nitrite levels were 0 ppm and the nitrate levels were below 10 ppm.  The pH was between 8.2-8.4 and temperature was 76 degrees F.  These results are consistent with the testing I conducted everyday for the past 5 days.  I wanted to make sure that the levels were not varying as the tank was cycling. <All good values> Last night I bought a number of different hermit crabs (Halloween, cone, blue legs, and a couple of light red legged hermits that I can't identify yet) and a porcelain crab from Big Al's Aquarium services in Ontario, Canada (Most reputable and knowledgeable place in Ontario, in my opinion).  I dripped the hermits and porcelain crabs in for a while before adding to my tank.  When I first put them in, they looked okay, some were walking around and others were just sitting put shifting through the sand.  When I woke up this morning, most of the hermits were out of their shells and lying still with subtle twitches from time to time. <A clue here> I think it might have been the temperature. <Mmm, no> If the water quality was off, then all of the hermits should have died, but the blue legs are still alive.   I adjusted the temperature to 82 F and turned on the lights (2-175 W 11,000K MH and 2-VHO super actinics) to warm the tank up.  It seemed that it might have worked a bit as many of the larger hermits were moving more and even walking.  They were still out of their shells though. <...> My questions are:  Is there a chance that they will recover if temperature was a factor? <Would be if this were a factor> What are the chances that they will get back in a shell? <Small>   What measures should I take the next time I introduce species in to my tank, especially fish and coral, which I eventually want to have (if I don't kill Anything else that is? <Yes... other measures... biomineral (mainly calcium and magnesium) and alkalinity> I thank you for your help, Andrew <Please read here: http://wetwebmedia.com/hermitdisfaqs.htm and the linked files above. Bob Fenner>

Lazy Scarlet and Blue-legged Hermit Crabs   11/5/06 Hello crew at WWM <JM> just a quick question I have blue and scarlet hermits that lay around all day (for days) and are still in the same place the next morning --- <Trouble... something likely amiss with your "water quality" here... possibly endogenous poisoning...> no they are not dead (smile)-- however they are not actively feeding on the algae, in which I purchased them for. <Most species of Hermits are not so inclined to do so... if there are other types of foodstuffs available>   I also have zebra-legged which are constantly feeding.  I won't go into the parameters in my tank except to say that corals, fish and other inverts are thriving alive with voracious appetites) Nitrates are less than 20 ppm. Generally I do not use supplements except I do use Kalkwasser and a few (5) of drops of iodine (Kent marine) twice a week in a 75 gallon tank. I do feed the tank for the Brittle stars, maroon clownfish and the blue-lined surgeonfish (Acanthurus nigroris.  The question is if I am feeding the tank are the hermits losing interest in the algae because they are scavenging? <Yes... you are likely correct here> and is there anyway to encourage them to eat algae short of placing them on the live rock with the algae? <Heee! Making other foods scarce> and lastly I understand they are generally hardy is there a particular tank parameter that needs to be checked that would have a negative impact on the crabs?? <Mmm... are actually "false crabs", anomurans... Need biomineral, alkalinity as per your cnidarians... other essential macro and micro-nutrients can/should be supplied via feeding...> Thanks in advance for your response <Welcome. Bob Fenner>

Halloween Hermit Crab (Ciliopagurus strigatus) care  - 08/26/06 Hi know from reading on your site you don't like crabs in a reef tank but I do have a few. (Crabs & questions) I think my Halloween Hermit Crab is dead I cant tell if he is still in his shell. In the past he has molted and I could swear he was dead but than in an hour he would me moving and by the next day back to his old habits. But this time it's been about four hours. All parameters seem OK PH 8.2 Ammonia 0 Nitrate 10 Nitrite 0 temp 78-82 1.024. The only thing I think of is that I replaced some evaporated water and the salinity went from 1.025 to 1.024 could this be enough of a change ? <Mmm, yes, to effect this behavior, possibly kill Hermits> I have 2 Petrolisthes sp I feed them DT phytoplankton every other day 1 emerald & 6 scarlet red crabs. At night I drop 2 pieces of sinking food tablets in the tank. Is this sufficient food for the crabs there's algae growth green & brown & coral line. Thanks <They will "let you know" if insufficient food is offered... by feeding on each other and the other life in the system. Bob Fenner>

Alkalinity and hermit crabs... I'll say! Not even trying to read   8/23/06 Greetings, I recently have had a horrible experience losing about 40 scarlet hermit crabs on two separate occasions.  The hermits were added just after cycling the tank. <This could do it>   The symptoms before loss was extremely unusual -- complete stillness for a period of time, and then crawling out of their shells with no apparent signs of distress, <! Crawling out of shells, stillness are apparent signs...> climbing around (usually upward) for a time, and eventually dying without ever going back into their shells.  The first time I had a huge loss I found out that my water had an unexplained nitrite spike.  (Unexplained because there was no ammonia spike before that -- I had been testing daily). <...>   I believe that the new saltwater I'd been mixing up is the problem (as it tested at .5 in ammonia upon mixing), and changed salt mixes.  But a few days later I had a second die-off.  After testing my water quality, the ONLY thing wrong with the tank is that the alkalinity was outrageous. <Also toxic...> Like someone who didn't know better, I'd been trying to combat my continuously dropping ph by adding buffer about every other day. <How?> I'm told that this caused me to have a high alkalinity.  Is this fatal to hermits? <... yes> I also lost my peppermint shrimp on the second occasion I lost a bunch of hermits, but the ghost shrimp in the tank were not affected.  Do the symptoms I mention re the hermits sound familiar? <Oh yes... as you would know had you followed directions before writing us and read what is already posted...> I'm told it is extremely rare for them to leave their shells. I have stopped using buffer and am still battling a low pH, which remains about 7.9 to 8 no matter what time of the day I test (morning and night).   My substrate is aragonite ("live") from Petco.  Right after doing water changes without buffer to decrease the alkalinity, the few crabs I have remaining got more active and are doing fine, despite the lower pH.  Did I read on here that new substrate can affect pH in a negative way? Thanks for your help! Emilie <Have just skipped down. Please start reading here: http://www.wetwebmedia.com/hermitdisfaqs.htm and the linked files above... "But wait, there's more!"... Keep reading re the other issues you have questions re above... the search tool, indices... BobF>

- Dead Crabs 8/21/06 - I've had a 20 gallon saltwater tank for several days now, but I can never seem to keep crabs alive. I at one point I had 5 hermits, all dead. Just recently I had a sally lightfoot but like the rest, it started to change colors (pinkish) and died. I guess its my water quality, but my LFS only said to check for ammonia, nitrite, nitrate, sg, and ph (they are all in normal ranges). Do  I also need to test the Ca, Alkalinity? anything else? Also I was told I  wouldn't need a protein skimmer since my tank was only a 20, and that's why I never added or tested chemicals like calcium and iodine. Do I need  one? thanks, Andy <Seems to me that if your tank is only 'several days old' then you need not be concerned at this point about calcium or alkalinity. I would consider your source of saltwater, although with things still cycling and such, I'd really wait until everything is fully settled in a couple of weeks to make any judgments. I'd keep trying on the crabs and perhaps consider some other methods for acclimation. More about that here and the FAQs beyond: http://www.wetwebmedia.com/acclimat.htm Cheers, J -- >

Blue Spotted Jawfish ... beh., hermit health, supplement use...   5/9/06 Hi, I have a 75 gallon reef tank. Everything in my tank has been doing fine. I have a 4-inch Yellow Tang (Zebrasoma flavescens), 3-inch Clown Tang (Acanthurus lineatus), <Not easily kept> 3-inch 5 Bar Mystery Wrasse (Pseudocheilinus ocellatus), 1 1/2-inch Sixline Wrasse (Pseudocheilinus hexataenia), 4-inch Lawnmower Blenny (Salarias fasciatus), 3-inch Hawaiian Cleaner Wrasse (Labroides phthirophagus), <Ditto> and just purchased a 3-4 inch Blue Spotted Jawfish (Opistognathus rosenblatti ). I have a hammer coral, a torch coral, a Lobophyllia brain coral, a Kenya tree coral, and a couple button polyps. The lighting is four 65 watt compact fluorescents and one 40 watt regular fluorescent bulb. The sand/coral rubble is about 4 to 10 inches deep (ten behind the rocks and about 4 to six inches in the open). There is a 55 gallon sump, about 60 lbs. of live rock, two Magnum 350s (one on the sump and one on the display) display one only runs carbon), a Whisper 60 on the display for circulation with nothing in it and the main pump is a Via Aqua pump (600 gph), and there is a sea clone protein skimmer on the sump too. I have 4 questions. 1) I had a Electric Blue Hermit Crab (Calcinus elegans) in the tank. It always was in its shell and seemed tipped over. Plus whenever I put it on the rocks it would fall off and didn't move much. Why is this? <The item you mention below, the addition of supplements directly to the system is very likely the root cause here> 2) That same hermit crab was dead after the addition of the Blue Spotted Jawfish. I saw what was left of its legs along with the shell on the bottom. Could the Jawfish have eaten it. <No, not likely> 3) In the back of the tank where the crushed coral and some sand reaches about ten inches deep the Jawfish decided to make its burrow there. I couldn't find it for two days and after one day I went out and bought a lid for the tank knowing they are jumpers. Its burrow is very deep. There is about 4 inches right on the back glass and maybe another 4 below because the fish is about 3-4 inches. I know this seems like a favorable spot seeing as he/she can have such a nice burrow but is there anyway that it will maybe come to the front of the rocks or tank so that I won't have to go behind the tank to view it? <Not likely, though it may become more outgoing with time> 4) My hammer coral keeps its polyps retracted almost all the time. They aren't completely retracted but they aren't out like they are suppose to be. My torch coral is doing great along with the others and both are on the same level in the tank and the torch might be getting slightly less light than the hammer coral. I threw that in because both are Euphyllia corals. Calcium is added daily and strontium molybdenum is added every Sunday. Can you tell me why this may be? <... not a good practice to add such supplements directly to tanks. Add them through your regular water changes, through pre-mixed water... Covered on WWM. Bob Fenner> Thanks, Tim Morrissey P.S. Do you have any really cool ideas as far as fish for my tank? Also considering the bioload I have now, about how many more fish could my system handle? <Your system is already "full-up" fish-wise with what you list. Bob Fenner>

Molting mishap?   1/18/06 Hello Crew! <Laura> Firstly, I just love your site--the amount of information that you have shared is amazing! <Lots of good help> I have searched your archives but I can't find an answer to my question; I hope that someone can help.  I have a 20-gallon marine tank, which has been problem-free.  I do weekly water changes and check the water conditions with a home test kit.  After doing partial water change this morning, along with the weekly dose of iodine, I noticed that my beloved red-legged hermit crab, Senor Crabs, seems to be having some difficulties molting. <Very hard to match water quality with such a small system... and slight differences in chemistry, physics...> I wasn't aware that they molt during the day, <Night or day> so it was quite a surprise to see it happen. Everything looked normal at first--his old body was out of the shell and a white sheath was attached to the old exoskeleton.  The sheath was moving, so I assumed that Senor Crabs was in there and would be making an appearance soon.  I went out for a few hours and returned home to find a hitchhiker snail sitting on the poor crab, which it is totally out of the shell, just laying on the sand.  The white sheath is still attached to the old exoskeleton and I can see something dark inside the sheath.  Is this the end of Senor Crabs?  How long does a molt usually take? Thank you, Laura <Minutes to a few hours... You do have sufficient alkalinity, alkaline earth content? Perhaps this Hermit is/was "just" old... Do hold out... it may be still about... elsewhere. Bob Fenner>

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.>

Lee's Protein Skimmer, Sandbed, Blade Plant Question  11/11/05 Dear WWM, <Armand> Sorry about this super-long, multi-topic email. <No worries> First, I want to share my experience with a Lee's Medium Protein Skimmer (Countercurrent). <Not a top performer...> I have had it for two weeks.  Was having many problems with my aquarium - things dying, lots of green algae and diatoms growing.  I bought a protein skimmer for $28 Amazon.  The protein skimmer has been remarkable.  I consistently pull about a half-cup of brown-green-tan liquid out every other day.  My aquarium water is crystal clear.  My corals are opening again.  And the algae growth has slowed. Second.  My sand bed ranges from 1.5 to 4 inches deep.  Looking at the sandbed from the sides of the aquarium, the subsurface looks dark gray in some areas, green in others, and brown elsewhere.  Is this normal? <Mmm, for a system with too much nutrient, yes...> Should the sandbed be dark colored or should it be uniformly sand colored (light tan or white) from looking at it one the side? <Some color... growth of algae, other organisms is to be expected> How do I know if the sandbed is anaerobic or toxic? <... test kits, poorly colored organisms... acting oddly, dying... Sometimes smell...> Looking at the side, one can see many worm trails.  I can see worms at night - different colors, mostly spaghetti type. <Ahh! A good sign> Third, I have 5 blade plants in the aquarium.  They have new growth but are getting covered in diatoms.  Is this ok?  Should I brush the diatoms off? <I would> Fourth, though my aquarium looks better and water tests all come out fine, and pH is 8.1-8.2, my blue-legged hermits are slowly dying.  They are exiting their shells.  I am thinking that they finally are dying from the stress of the pre-protein skimmer days. <Maybe... can happen> Also, I have not put any food in the whole month to try to clean things up.  Are they just starving. <Possibly> There is a lot of algae yet to eat.  My snails are doing fine and a lettuce slug is too. Help! Thanks, Armand <Likely a chemical imbalance... calcium/magnesium, or alkalinity issue as well... Please read here: http://www.wetwebmedia.com/hermitdisfaqs.htm and the linked files above. Bob Fenner>

Drum noise and marine hermit crabs  09/13/2005 Hi Helper Guys!     My grandson has a huge drum set in his small bedroom, and a ten gallon aquarium 2 feet away, on a stand.  He had about 20 fish that quickly died, and our local pet store fish expert said it could've been heart attacks from the extremely loud noise from the drum set.  I had the water checked a few times a week at the pet store, and it was usually fine. Once it barely registered bad so I did a water exchange until it registered good. They were regularly fed, too.  There are still 2 sucker fish in the aquarium that are alive, but the pet store said they are very hardy and have thicker skin.     Anyway, now he wants to put marine hermit crabs in the aquarium, and we were wondering if the same thing will happen to the crabs when he plays his loud drums.  Thanks so much for your help. The pet store said the crab's shells would protect them from the noise, but I'm not sure that they really knew the answer, and so I wanted an expert's opinion. <Vibrations will and do cause undo stress on aquatic animals.  James (Salty Dog)>                                                 Coreen Bousfield

Electric blue hermit crab not moving since a week... oh oh 7/14/05 Hi! I bought an electric blue hermit crab and he was doing fine for a week. I bought him 6 empty shells of different sizes. After a few days he changed for a much bigger shell. About 48 hours after changing shell he stopped moving and stayed in his new shell without moving, since a good week now if not more. I tried to pick it up to see if everything is right but he opposes resistance and I was afraid to damage him so I left him on the LR without seeing anything. Could he be molting? Could he be dead but still hanging hard to the LR? Thanks! Dominique <Likely something is off in the system chemically. Please read... before writing: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm and the linked files above re systems, nutrition, disease... Bob Fenner>

- Staghorn Hermit Crab - Hi, We've had a Staghorn hermit crab for some time now and have noticed that over time his shell has gotten dark and shriveled-like.  I'm assuming that it is dead or dying. <I think you are correct.> Tonight, we have noticed that the crab has abandoned his shell and has moved into one of our spare regular hermit crab shells.  But has not managed to flip the shell upright yet (too big perhaps?) <Perhaps give him some help.> Will he live in a regular shell? <I would like to hope so... as neat as Staghorn hermits are, they rarely get to live for long in captivity because their shelter just doesn't make the transition. Perhaps this one will have a better chance because it's moved on.> My husband has put a few smaller shells around him. Is there anything else we can do for him? <Flip him right side up.> Other info about tank: 55 gallon tank 260 watt light tank mates: coral beauty angel bicolor angel clownfish several damsels snails cleaner shrimp 2 electric blue leg hermits 1 red hermit Any advice is greatly appreciated. Thanks! Kimberly <Keep an eye on him, and make sure he gets upright. Cheers, J -- >
- Staghorn Hermit Crab, Follow-up - 30 Jun 2005
Thanks for getting back to me so quickly and for providing me with all your input. <My pleasure.> By the next morning, he was upright and doing his thing (sifting sand) as always, just like he did when he was in his original shell.  Now, several days later, he seems to be doing fine. <Excellent - glad to hear.> Thanks again! Kimberly <Cheers, J -- >

Marine hermit crab question Hi there.... I tried to find my answer on here but I didn't see it.  I have a 55 gallon tank with two blue damsels and two striped damsels and one marine hermit crab. The crab molted about two months ago ( we purchased him three months ago) and has been fine ever since he molted. Well about a week ago he went into his shell and never came back out. My question is.... how can I tell if he's dead? <Mmm, should be moving about, feeding... if it doesn't move in a few days...> I mean we have land hermit crabs and I know they fall out of the shell if they die but I wasn't sure if the marine critters were diff?? <About the same> He seemed to be doing fine up until last week and then he just went into hibernation... any info you could give me would be greatly appreciated!! Thanks- Melissa <These anomurans do "pass" for a few general reasons... Which am sure you've gone over on WWM... water quality, predation, toxicity... Bob Fenner> 

Dying Hermits (8/23/04) Hey there WWM crew! <Steve Allen tonight> I have a question about the hermits that I keep/have kept, in my 35g FOWLR and inverts tank. I haven't found and FAQ's on this particular problem, so here goes. My tank's been up and running since January this year and I've had my ups and downs with it, but one thing that has constantly happened, since I've started this fascinating hobby, is the fairly rapid demise of every hermit (both red and blue legged) that I've ever put in there.  My water parameters are: Sal: 1.021-1.022 <low for inverts; they really prefer 1.024-26> Temp:80 <on the high end> pH: 8.0-8.2 <a bit low, but OK> Ammonia: 0 Nitrites: 0 Nitrates: Fluctuating from around 10 to 35 (but I've never let it remain high for long) Calcium: 420ppm Prism skimmer <Not one of the better ones, are you getting a proper amount of skimmate?> Juwel in tank filter And about 8kg of LR. The hermits never seem to last longer than a couple of weeks or a month max! I've seen them crawl out of their shell and just die there and then on the floor, and others have seemed to remain upside down with their legs sticking out and billowing in the current for a few days, being dead upon closer inspection. I've also attempted to keep a couple of turbo snails who lasted for about three days before snuffing it! The fish I have in there are 2x false Percs, 1x Firefish and 1x four-spot wrasse (can't seem to find much info about this particular fish!), so I don't think it's the fish killing them off!
<A web search reveals that this common name is used to refer to several different species. Try searching on the scientific name of your particular one.>
So far I haven't tested the alkalinity…do you think this might have something to do with it even though the pH has remained stable?...if so can you recommend any good test kits I should use and do you know what level the alkalinity should be at? <read here: http://www.wetwebmedia.com/alkalinity.htm> Thanks for all the help you can offer, I really need to get to the bottom of this before I add any more of the poor little buggers! -Mark Essex, UK.
<Well, Mark, it could be that they would do better with a more properly oceanic SG of 1.024-26. How do you measure? You may find it's way off if you use one of those cheapo plastic hydrometers. Consider having your LFS test with a refractometer. Good test kits are Hach, LaMotte and Salifert. You might want to upgrade your filtration a bit if you're not getting much skimmate. Gradually dropping the temp a couple of degrees might help too, but this is likely a minor factor. Are you running carbon periodically to take out potential toxins? How often do you change water? Any number of strange things may be affecting them. Start with SG. Perhaps your pH is dropping at night--check it in the wee hours. Stable pH in 8.2-8.4 range would be best. This should give you some things to investigate and work on. Hope it helps.>

Hermit Die-Off (4/19/04) Hi, I seem to be having a problem with my 6 scarlet reef hermits. I have had them for two months now. I bought them a month after cycling the tank. They are in a 72 gallon saltwater tank with 75 lbs of live rock ( that was fully cured before introducing the crabs ). A week ago, I lost the first one. He had crawled out of his shell and was halfway across the tank where I found him dead. Two days later, I lost another one. He was in his shell, but hanging out of it, dead. Two days after that, I lost another one. Same scenario, hanging out of his shell dead. Then this morning I found a fourth dead, hanging out of his shell. The water parameters are all 0. (Nitrates, Nitrites and the like). <what is the specific gravity?--all inverts tend to do better closer to normal seawater. pH? Tem? Are these all stable?> This tank has been running for 2 and a half months. No fish yet. ( Still in quarantine, they came in sick. ) I add iodine once a week for molting ( I also have a camel and a blood shrimp. I lost my peppermint to what appeared to be a molting problem, so I bought the iodine.) <Best to test levels of anything you add.> I have a dozen or so dwarf blue, red and zebra crabs. They are all fine. My shrimp and snails are good too. Three weeks ago, I did receive an order that included the red legged and zebra crabs, as well as an electric blue crab. Everyone is fine but the electric blue did die a week after he arrived. I also lost the banded Trochus snail that came with that order as well ( He, actually I believe she, had just laid eggs the day before she died. ) On two of the crab shells, I found what I thought were small feather duster worms, but I was told it was Aiptasia. Could that have been the problem? <Harmless to the hermit, but can be a big problem for the tank--read the Aiptasia FAQs.> I see nothing wrong here otherwise. I have over 2 dozen shells of all sizes in the tank, so it was not territorial aggression. My Scarlets have spawned three times in the last month. Is this normal afterwards? <Some inverts die after reproducing, others do not. I am uncertain about hermits.> What is there average lifespan? <I'd guess at least a couple of years--some a decade more.> Could they all just be old? <Possible, not probable.> I bought them all at the same time from the same store. Is there maybe something that came in on the new stock, that is effecting just the Scarlets? <The fact that it is not affecting your other crabs and shrimp does suggest something specific to them rather than a more generalized toxin or pathogen, but I am not aware of a pathogen specific to this species.> They are my favorite and I would love to get more, but I want to make sure that the new ones won't have the same fate. Sorry for the lengthy email, but this is breaking my heart. <It's always tough to lose animals, no matter how "primitive," especially when the cause remains a mystery.> I am trying so hard on this tank, and everything that can go wrong, appears to be doing so. Thank for the info. <I'm stumped here with this scenario. I'd suggest you start a topic on the WetWebFotos forum under "Marine Invertebrates" and see k a range of opinions/theories there. Steve Allen.>

Hermits & Parasites (1/9/2004) Hello everyone: <Steve Allen here> I did check your articles and the internet and could not find an answer to this question.  Do saltwater hermit crabs carry parasites on their shells <perhaps> and should they be fresh water dipped before being put in a new tank? <No. Instant death to the hermits. Better to quarantine before putting them in your tank, though the risk of parasites is small.> Also I am cycling <how long> a new tank(20 Gal.) with a blue velvet damsel. <I recommend against cycling with fish. Needless suffering for them. Fish are not needed for cycling. Search WWM for info on how.>  The Sg is 1.026, Ph 8.2, Temp 79, Ammonia .25 and nitrites are 2.0.  I do at least a 25% water change every other day to bring the nitrites down.  I have noticed that the damsel is scratching frequently and have read elsewhere that this could be irritation from the nitrites. <yes> I gave the fish a freshwater dip before introduction into the new tank.   The fish has a voracious appetite <good sign> even now with the nitrites as high as they are. I have not seen any obvious parasites or white spots on the fish.  He does come up to the surface(2" below) frequently in the corner where he is fed so I am assuming he is checking for food.  Can the nitrites cause the damsel to scratch or does the fish have parasites? <If you do not see spots on the fish, it is more likely the toxic effect. Get these numbers down, but don't change too much water or you'll never get it cycled.> Thank you guys for your help and great articles. <Glad to be of service.>

- Healing Hermit - Hi there, <Hi, JasonC here...> I have a red legged Hermit crab which I am really worried about. He did he usual hiding before shedding. Disappeared into his nice little cave I made for him. He shed his skin late Friday night. I noticed he was hiding inside his shell on Sat. He usually remains grumpy for about a week after shedding. However on Sun he came out of his shell and was missing his big pincher and all his legs down the left side. I don't know if one of the fish pulled him while he was weak or if he just decided it was a good time to loose his shell. <Dropping a limb is an ability crabs and lobsters have that allows them to get away while leaving something behind to distract/appease the predator.> I left him in the tank to reduce his stress however I noticed that some of the fish were bothering him. So I moved him into the sump. He seems to be fine and he is eating etc. I have knocked the calcium level a bit higher to give him more calcium to recover. Don't know if this will help. Is there anything that I can do to help him heal faster. <Not really, you did the best thing by removing the crab to a quiet place to stave off aggression. The limbs will grow back with successive molts. No worries.> Thanks, Rob. <Cheers, J -- >

Sick marine hermit crab- 6/4/03 Hello Almighty fish-helpers, <Howdy!> I have a common Hermit Crab (yep, the red hairy leg variety).  He (or she?) <depends on how hairy <G>> has been in the family for about 8 months. Up until recently he's been happy in his 75g saltwater fish-only tank. He seems to rule the roost. <they can be rowdy indeed> I've always provided him new shells to check out and he moves into one now and then. The last week he's been hanging out in the corner, not moving much and not as eager to get around the tank.  He eats much less and seems to have the blues. Any thought? Thanks, Steve HJ <perhaps lack of iodine for proper ecdysis/molting. Iodine is critical for it, and yet is only good in solution for hours/days (part of the reason for recommending small weekly water changes instead of monthly or longer). If the tank gets not iodine/reef supplements and/or has been light on water changes, the little bugger could be starving for iodine. When in doubt, do a water change... 25-50% to see if that stimulates it. Also test your water chemistry: has pH strayed low (below 8.3?), is ALK flat (below 8 dKH), etc. Best regards, Anthony>

Scarlet Hermit Deaths >Hi, >>Hi. >We are new to this hobby and your website has been a tremendous help!  However, we have a mystery that we can't seem to find an answer for. >>Thank you, you're welcome, and let's see what can be done. >After the tank cycled and the algae bloom subsided, we were left with a few small patches of hair algae and some areas of brown diatom algae.  2 weeks ago, we purchased our first clean-up critters from JEF.  6 tapestry snails and 10 scarlet hermits. 2 scarlet hermits died the second day.  pH and Alkalinity were low (7.8 and 2.1 respectively), so we slowly added Seachem pH buffer.   >>Hhmm... pH is a tricky thing to be messing with.  I wouldn't make changes any larger than .1-.2/day.  The pH is indeed low, but what about specific gravity? >The scarlet hermits have continued to die - one or two every few days.  We left the bodies in the tank, just in case it was molting.  Most of the time they had crawled out of their shells - and their little bodies were still in tact for days (so we assumed it was not a predator).  The really weird thing is that eight of them came to the same area of the tank to die (within inches of each other)!!! >>No answers to that. >We lost the last one today.  He had been really active and was on top of a large rock eating yesterday.  Today, his shell was empty and a 3 inch long bristle worm came out of it.  He is the only one that has apparently died at the other end of the tank (one is still missing).  All six of the tapestry snails seem perfectly fine.  A friend offered to give us a few scarlet cleaner shrimp.  Now we are afraid to take them (don't want to risk their health).  Can you help us figure out what to do?  Also, should be buy a wrasse get rid of the bristle worms? >>No, the worms are there for a reason, and they do perform a function.  If they seem to be of "plague" proportions, you definitely have a nutrient/excess detritus issue.   >Thanks!!!  Dave >The tank is a little over 2 months old - 110 gallon (29 inches tall) with about 85 lbs of live rock and an ecosystem filter (with Caulerpa) sg  1.24 (swing arm tester) >>Poor choice for a measuring tool, in my opinion. temp 80 Alk 4.8 pH  3.0 >>This can't possibly be right, can it?   >nitrites  0 nitrates 0 >>Curious about test kit brand/reliability.  If your specific gravity is indeed spot on, then I am at a bit of a loss, as there is nothing I can think of that would kill only the hermits and nothing else.  I would indeed try the shrimps, one, maybe two, just to see.  Acclimate slowly and watch.  Double check your test kit(s), as well as your hydrometer against something a little more reliable (my own affordable preference are floating hydrometers).  Sorry I can't be of more definitive help at this time, but maybe you'll find something by double checking the kits, etc.  Marina
What is Killing our Scarlet Hermit Crabs?
>Thanks.  We bought a good floating hydrometer.  Salinity is right at 1.024.  Two people have told us that some worms including certain types of bristle worms are dangerous (can kill).   >>Bristle worms will eat what is dead, I doubt very seriously that they are an issue. >We bought an arrow crab that we are very slowly acclimating.  Did we make a mistake?  Also, if we should keep it - do we need to quarantine it (this early in the reef stage)?  Dave >>Personally, I believe in quarantining everything, including inverts.  You've purchased the arrow crab to eat the bristle worms?  If so, consider instead that the bristle worms perform a function, as well as indicate a possible buildup of detritus, as I mentioned previously.  Marina

New Tank/Hermit Crabs Hi, I have a new 29 gallon marine setup than has been curing for 5 weeks now. <Wow! Very new to the hobby??? Welcome to a world of wonderment and addiction, mate>  Its a live rock system. I have checked the water for ammonia, nitrite, PH and salinity, all of which turned out fine but just to be on the safe side I also took a sample of the water to my local marine specialist and again it tested fine. <Very good. I always use a few test sources just to calibrate my own findings> So I bought 5 hermits and 4 snails to help clear the tank of the algal growth that had covered the rocks, glass and bottom of the tank. <OK> About 2 hours after I had introduced them I checked on them and 3 of the snails were almost dead on the bottom with the other 2 still on the glass but very weak. <Did you acclimate?? Should do so over a long period of time if you ask me. Sometimes a huge difference in water quality between your tank and the dealers. The process for inverts from a dealer to my tank can take up to 2 hours and even more in extreme cases (starfish)> Also 3 of the hermits were hanging out of their shells looking dead and the others again weren't moving around and looked very ill. <Interesting> I immediately took the hermits out of the tank and they seemed to recover a little in the air. <depending on what hermits may have been necessary. Some hermits work intertidal areas meaning they sometimes need a little air from time to time> The tank has a red algal growth covering the rocks that looks like velvet. <Sounds like Cyano-bacteria. See here: http://www.wetwebmedia.com/bluegralgae.htm > Could this be the problem or is something else causing these animals to die? <It is A problem, but not in the cause of death in your hermits and snails. Check the posted links for more information regarding bacteria-bacteria. As far as cause of death for your inverts I couldn't say. If parameters are all in check, try a longer acclimation time. Make sure you are getting quality livestock by watching the animals making sure they are active and have been in store for awhile. (not a good idea to new arrived shipments from a dealer) Quarantine if possible. -Paul>
Dying hermits - 11/20/03
The only thing I knew about acclimating was to leave the tank in the bag for a while. Though I have just been informed about slowly adding small amounts of tank water into the bag. The hermits are a reef species so I don't know if they require air but they didn't have any in the suppliers tank. <you would be surprised! Many species of hermits require a spot to grab some air. Not all, but again, there are a great many who can take advantage or air. In any event, not "THE" issue here in my opinion.> The animals had been at the dealer at least a week. <Very good. I think the issue here was that your acclimation procedure was improper for these animals. There is likely a disparaging parameter between your reef water and the dealer holding water. Keep that in mind with all your additions -Paul> Oh and thanks for replying. <No problem.>

Hermit death sleuthing Alright, I wrote you last week about clown fish and scarlet reef hermits. One of the hermits showed up dead this morning, out of its shell, like it crawled out and then expired. The other one I have not seen today, and though it was quite active on Friday, I am concerned it kicked. Water tests, using an Aquarium Systems test kit yielded the following results--no ammonia, a range of 0.2-2-mg/l of Nitrite and a range of 0-10 mg/l of Nitrates, salinity 1.024 and ph 8.2. Three questions: 1. How long does it take for my tank to do a cycle using cured live rock. Is it possible the tank is already on phase 2 of its cycle even though I only added rock 4 days ago? 2. Was the crab molting and died or what happened--any ideas? 3. I am noticing an increase in the brown diatom algae--what can I adjust in my water to make this go away? Jeff Ranta < 1) Jeff, next time wait on the livestock till your system has completely cycled; zero ammonia and nitrites. Some well- to completely cured Live Rock will present a situation of pre-cycling by itself, but this is rare. In some situations, where the rock has a lot of dead biomass, or is killed off by its handler(s), cycling may be delayed for months... This is why one needs to measure things like ammonia and react (generally with massive water changes) if conditions become deadly (to the live rock organisms). Keep checking your nitrogen cycle parameters; you should find no nitrite and growing nitrates with establishment of cycling. 2) The crab probably died from outright chemical stress, from the die off, and respective changes brought on by the cycling. 3) The Brown scum/diatom algae you mention is a good sign! This indicates succession, cycling that is producing nutrients and viable conditions for other life... I wouldn't disturb it as yet. Wait till you see it being supplanted by Green algae, this will happen soon. Patience my friend, Bob Fenner>

Hermit crabs I find a dead hermit crab in my tank, laying out of its shell, every week.  It is always a scarlet reef hermit. I have blue leg, and left/right handed hermits in the tank. The other species of hermit never die. Are the other types killing the Scarlets? The Scarlets are by far the biggest hermits in my tank. Thanks, Jared < It's possible as all crabs are outright opportunistic omnivores... but there might be another reason for your Scarlets passing... For instance, do you know how much Calcium and Alkalinity are part of your system? You/they need both... and how about an assortment of shells for them to "upgrade" to? As Hermits grow, they need new, larger homes... And if they get caught too long outside... may fall prey to other predators. Bob Fenner>

Red legged hermit crabs Bob, I have an aquarium with two eels, Koran angel, 2 red cardinals and a grouper. the tank has been up and running for years, but I can't seem to keep hermit crabs alive. Also snails don't have a problem. All the fish are happy and healthy, is there something special that my water could be lacking or some type of care. Thanks Crab less in St. Pete <It's likely you either are missing something in the way of alkalinity and/or calcium in your water (you can get test kits for these, and modify their values)... or too much of something, like a metal residue from your source (tap) water, contamination from some part of your decor (a tramp metal, like a part of a pop-top lid in your gravel, or a metal thermometer)... Check for sources of metal in your system... a rusty screw in a lid? a metal clamp on part of your plumbing? Bob Fenner>

The mysterious hermit crabs . . . Bob, I enjoy your daily FAQ on the FFExpress site - Thanks for helping us "newbies" out. :) Do you have any idea how long a hermit crab will live and how big it will get? I have 2 - a blue legged and a tan one (it has the big left claw). The blue legged crab hasn't grown much, but the tan one has outgrown 3 shells in 6 months. At that rate he will outgrow my 30 gal. tank quickly. Also - should I feed these crabs or let them find their own food? I have been feeding the tan one frozen brine shrimp and I'm thinking that the reason it's grown so much. Thanks, Brandon >> Thank you for writing. Some smaller species of Hermits only live a year or so... some of the humongous ones several years... And yes, I mean no to feeding yours directly. Don't encourage their growth... they'll live longer, healthier lives by "just" scavenging... and probably be much less inclined to "get into trouble" nibbling away at sessile livestock and coralline algaes... Bob Fenner

Hermit Crab Bob, I have had a Red Legged Hermit crab for approx. 5-6 months in a FO 60ukG tank. All has been OK for those months, as he has been keeping the tank nice and clean and roaming around, occasionally shedding his "skin". Two nights ago I found it on its back and therefore hiding in the shell. I assumed he had fallen off the rocks in the tanks and could not right himself - I waited a while (1-2 hours) but he did not even come out a little bit. I did the honors by placing him right way up but he never seemed to come out of his shell. He came partly out but then retreated somewhat. Last night I discovered that he was in fact dead and therefore removed him from the tank, shell and all. There are no other signs of illness in the tank and no problems with any other fish over the past few months. Water parameters are OK (pH is a bit high - above 8.6) and all other fish are OK! <Hmm, am concerned about how/why your water pH is so high... this could be the very cause of loss... not uncommon that supplement "shock" is for hermits, snails, cucumbers, Seastars...> Could he have been shell shocked?? <Hmm? A 'Nam vet? Not from falling... and no worries re Hermit spatial orientation... healthy ones are very able to right themselves.> Any suggestions? Thanks in advance. Scott <Just to investigate your water conditioning practices, test kits... Bob Fenner>
Bob, Having sent you an e-mail on my Hermit Crab, I meant to add a further question. When making water up for a routine water change I get a "scum" on the top of the water prior to adding it to the tank. I use de-ionized water and add a re-mineral M additive and salt. I then aerate this using a pump for 12-24 hours before changing. It is after this aerating that the scum appears. In order to stop the scum entering the tank on a water change I filter it through a sponge and this seems to work. <The sponge is a good idea... but would aerate, store the new water for a good week... > I have not seen any noticeable affects on the fish or water quality apart from a rise in pH (it was stable at 8.6 from start but now raised to above this). <You need to check your alkaline reserve... I suspect that you have insufficient carbonate, bicarbonate content in your water... and I would vastly cut back on the use of the "M" supplement> Is this normal and is it just being aerated too much or too vigorously?? I am now using the pump from my thrown away SeaClone (replaced with a Turboflotor on your advice - much much better!!) - a 1000l/h pump (I think!) <Not un-normal... but also not a good sign/indication... you don't want to have a permanently elevated pH... many potential problems with this condition...> Is there anything I can do to lower the pH or should I wait and see if it cycles? <Cut back on the supplementing... get involved with the "madness" of adding buffers (precipitating out some of the cause of the high pH...), skip both and get on to using a calcium reactor, just rely on the added biomineral and alkalinity boosting of good salt mix (like the Instant Ocean products)... Really though, gaining an understanding about the aspects of pH, alkalinity and alkaline earth elements, their roles, interactions in captive environments... Please read over the sections and especially FAQs areas on these concepts posted on the site: www.WetWebMedia.com and seek out the books/references mentioned to read over their thorough treatments... buy, use testing... And...> Thanks again for your time, Scott <We'll be chatting. Bob Fenner>

Hermits, low spg, apparent aggression  Bob, Can low salinity precipitate vicious behavior in inverts?  <Hmm, can? Yes> One of the red reef hermits viciously pursued, attacked, and killed another one over the course of a day. He started by attacking him while he was in his shell and then after the little guy ran naked around the tank, he ripped a leg off. Last night the little guy was clinging to a rock and this morning I found him eviscerated on the ground. We lowered the salinity the day before from 1.020 to 1.019. Should we revamp our hospital tank (remove the copper) and put the inverts in there?  <I would not... Know that many hermits are "quite opportunistic" and given any shortage of food, shells to trade into (you should have some spares in the system...) will "go after one another"... even so-called "vegetarian" or "mainly greenery-eating" species...> We have 2 large red hermits and 2 cleaner shrimp left now? Or is that red hermit trouble and we should trade him in because he's got a destructive personality? <Maybe... Bob Fenner> Thanks, Allyson

Snails and hermit crabs Hello, I have a couple of questions about bottom feeders.... Do I need to quarantine snails and hermit crabs when I get them?  <Only if you suspect they may die easily, polluting your main/display system... if there are DOA's, the water smells badly... I would> How about dips, do they need that too? (I have read your book from cover to cover so I know about quarantine and dips :-) <I don't generally dip/bath snails or hermits> Also, I was wondering if cleaner shrimp and crabs get along alright (I'm thinking your book says "NO")? <Most species, most cases, no... many crabs will consume the Cleaner Shrimp, particularly at molting time> Thanks, Jana p.s. I am putting together my own, homemade protein skimmer right now and I tell you what - even if the dang thang don't work, I sure had fun doing it ! Everyone should make their own simply for the self-satisfaction. <I agree with your go-getter spirit. Good for you. Bob Fenner>

Hermit sick Dear Bob, I've read your archives on alkalinity, pH, hermits, hermits FAQ. Our red reef hermit has been hanging out near/on top of our bubble wand for several days now and I'm getting concerned. He'll usually slow down a bit before he molts but he does not look like he's eating (he usually takes food from my hand) and this has been going on unusually long. He also looks a little pale. Here are our water parameters. Do you think low alkalinity could account for this? <Possibly... you do have a place for it to haul all the way out of the water?> Can you tell me very explicitly how to raise the alkalinity in a way that is safe? <Simple baking soda... oh, I see you know from below...> You mentioned baking soda (we bought Arm and Hammer--are you sure there aren't dangerous additives)? <Hmm, yes... the only ingredient is sodium bicarbonate... you might want to use a test kit if you're concerned... there is very little chance of overdosing though> alkalinity=3 pH=8 ammonia=0 nitrite=0 nitrate=5-10 temp=82-84 salinity=1.022 We've had our tank since January and we're sparsely stocked in a 125 gallon tank with 1 Naso tang, 5 damsels, a cleaner shrimp, and the red reef hermit. We have a few chunks of live rock too. We gave our Naso tang new food a week ago (Spirulina pellets) and that's the only recent change I can think of. Our filtration is a trickle filter with BioBale and a carbon canister. I'm grasping a any other hypotheses. Thanks! Allyson <Mmmm, maybe just a pre-molting incident... Bob Fenner>
Re: hermit sick
Dear Bob, I've read your archives on alkalinity, pH, hermits, hermits FAQ. Our red reef hermit has been hanging out near/on top of our bubble wand for several days now and I'm getting concerned. He'll usually slow down a bit before he molts but he does not look like he's eating (he usually takes food from my hand) and this has been going on unusually long. He also looks a little pale. Here are our water parameters. Do you think low alkalinity could account for this? <Possibly... you do have a place for it to haul all the way out of the water?> You're kidding! I have not read that red reef hermits need to come out of the water! Is this really true? <Some folks dispute the possible benefits, need... but they are found out of the water (where they're collected) in the wild... and this one may need to "dry out" a bit> You don't think that if I take him out of water, he'll die? Hmm. I'm not sure how to engineer something he can climb on. <Good idea... even just a piece of Styrofoam anchored to the upper corner... Bob Fenner> Thanks, Allyson
Re: hermit sick
The little hermit is better!!!! I added 2 tbsp of baking soda last night and alkalinity increased by .5 (to 3.5) and this morning he's waltzing around!!! (although not as energetically as he typically does) My log books showed a slow drop in alkalinity over many months (you mentioned this is common with trickle filters).  <Yes, more so than other filter modes> The little fellow must have reached his breaking point. PH might have increased too (not sure-8 to 8.1, hard to tell). I'm going to increase alkalinity a bit more. I'm having trouble finding what is typical in our books but our test kit is saying the value should be 4-6 meq/L but Tullock says it can be lower. <Better to be a bit higher IMO> Wow, thanks. <You're welcome my friend. Bob Fenner> Allyson

Hermit Crab Mystery? what does it mean when a hermit crab loses both of his pincers at the same time? <That somebody probably ate them. -Steven Pro>
Hermit Crab Mystery II
He is alone and the pinchers are in the tank. <Perhaps he had some problems shedding? -Steven Pro>

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