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FAQs about Hermit Crabs 1

Related Articles: Hermit Crabs, Crabs, Marine ScavengersFresh to Brackish Crabs

Related FAQs: Hermit Crabs 2Hermit 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 ScavengersCrustacean Identification, Crustacean Selection, Crustacean Behavior, Crustacean Compatibility, Crustacean Systems, Crustacean Feeding, Crustacean Disease, Crustacean Reproduction,

Dardanus tinctor with Calliactis Anemones, Red Sea at night.

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>
Re: Snail & Hermit Crab waste
Hi Steve: I have a 54 gallon corner tank. I guess I should pull out some of the crabs and snails. What do you think? <Yes, I would remove all but two of each hermit crab. I would leave all the snails and if you need more algae eaters, get ten more Astrea, Cerith, or Nerites snails. I like to use a variety of snails as they all seem to prefer to eat different things. -Steven Pro>
Re: Snail & Hermit Crab
waste Thanks Steve, FFExpress should redo their Web Site about adding the correct amount of Invertebrates. ~Aram <Nothing in particular about FFExpress, but all of these places are in the business of selling. I never assume any salesperson, selling anything, knows everything about their product or wants to be my friend. Pet stores are all businesses, too. Just approach them as you should any business, as an educated consumer. -Steven Pro>

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

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

Blue leg hermit crab? Hi http://www.reefclub.or.kr/forums/showthread.php?s=dad061220736b909342997c6r=1 (language is Korean, so you can't read it, but you can see the picture) this is not blue leg hermit crab? no reef safe? what kind of this hermit crab? <Don't know this species. Not found in my reference works. Will post in hopes that others may identify, offer input. Most Hermits are not carte blanche "reef safe". Would pass on this one if you did not find, feel it is more toward that end of the spectrum. Please read here: http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm
thanks in advance.

Hermit crab anemones Hello, how is everyone tonight, well I hope. <thank you, with the same wishes in kind to you. Anthony Calfo in your service> I will be doing so so so much better if you can help me with some info.  <I'll tell you what I know and make up the rest to sound very convincing <smile>> I have a fairly large hermit crab in my 30gal. long aquarium with an anemone on it's shell. From Dr's Foster and Smith's website, I figured out that it's a Calliactis polypus.  <Ughhh... fascinating but tenuous life for the anemone in captivity. I rather wish these animals were not made available for random impulse purchases. This is definitely one for the "I should have looked before I leaped" file. Please do research all animals, especially the unfamiliar before you acquire them, my friend>> But that's all the info I can find on it anywhere on the web. I was wondering if you could tell me what it's lighting requirements are.  <actually a heavily feeding dependant Cnidarian (organismal as absorption)> It seems to be doing well so far, I've had it a few weeks, and it's still fully extended all the time.  <which means little or nothing to tell the truth. Most all anemones can hang in there for several months starving to death while they execute normal polyp/tentacle cycles> When I feed it, twice a week, it grabs the piece of food out of my fingers and immediately curls around it to swallow it.  <very good to hear it! Please do continue to deed a wide variety of meaty foods (4 or more of marine origin) with the hope of keeping this animal for more than a year... hopefully years!> It also picks up little bits of "stuff" off the substrate as the crab moves around the tank,  <indeed... lighting is secondary to their feeding strategy for deriving sustenance> and every time the crab changes shells, it takes the anemone along. MY biggest worry though, is that it's not getting enough light because usually during the day, the crab goes under a ledge and digs into the substrate leaving only the anemone on top of his shell exposed.  <natural again for this heavily food dependant. Still, quality full spectrum reef lighting is attractive if not necessary for other live rock and invertebrates you might have. Bulbs favoring the 6500 to 10,000 K rating would be ideal. Several bulbs are most likely necessary> As I said, I can't find any info anywhere on this little guy. Any information you could give me would be sooo greatly appreciated!!!!  <explore the links to FAQ's from this site... perhaps info inside. Photos of a couple of hermits with their guests on this page too...http://www.wetwebmedia.com/marine/inverts/arthropoda/crabs/hermitcrabs.htm> Thank you, Kristen:) <best regards, Anthony>
Re: Hermit Crab Anemone
Hello again, <Hello! Steven pro with the follow-up.> I wrote before about the hermit crab anemone. I do take full responsibility for not finding out about it's care before I bought it, but as I said, I could find no info on it anywhere on the web other than what it was. <If no info was available, it would have been better to not purchase.> This little guy seems to fall under the same category as the mandarin fish and the sea horse, the pet stores are more concerned with selling them than keeping them alive. <Yes, unfortunately true. Mostly profit/market driven. If no one purchased them, no store would stock them. A vicious circle.> I wish I could have found some info on this thing, I figured it's like a curlicue-- low light and lots of feeding. I don't want to return it to the petstore and have someone else buy it and starve it to death. I'll just try to keep it alive as long as I can. <Agreed. Try your best and document your attempts and hopeful success.> Should I be feeding it more than twice a week? <Maybe every other day.> What I feed is : thawed of course, <An important note, please defrost with tank water, not hot tapwater.> Ocean Nutrition Very High Protein Formula, Sally's marine cuisine, tetra freeze dried shrimp, and very small crumbs of frozen krill and little bits of silversides. <All sounds good.> I also have about fifteen pounds of live rock and the glass, gravel, and rocks are crawling with those little Copepod things. How am I doing? <Sounds pretty good.> What else if anything should I be feeding? Thanks, again, Kristen:) <You are welcome. -Steven Pro>

New Hermit Homes I am new to saltwater tank keeping so please bare with my questions. <You are welcome here> I have a red legged hermit crab, he is very small, about a half an inch. I have read on your site (which is awesome, I use it all the time) that I need to have a larger shell available for him to "move into". When should I have this new shell available for him and where can I find a suitable new shell? Also, how much larger should the new shell be? Thanks for any help you can provide. <A good idea to have a few "other" shells about for "up-sizing" all the time. To assure these are "marine safe" I suggest getting a few from your local fish store, or e-tailer... in an assortment of just barely larger on up to about twice the size your Hermit currently occupies. Bob Fenner> Theresa

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

Hermit Crab 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>

Hermit Crabs I am doing a school project on hermit crabs and I was wondering if you knew the how long hermit crabs have been around, or anything about their general ancestry? please e-mail me back if you have the answers to these questions. thank-you <There are many types of crabs that live in different habitats... some in freshwater, some in brackish, some in marine... and some simply near water (but not underwater). The following page describes saltwater/marine crabs: http://www.wetwebmedia.com/hermitcrabs.htm>

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

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

What type of snail is this (actually Hermit Crab) I went to the LFS to get some blue legged hermits. I am not sure what in the heck these are can you help?  <Mmm, not to species... do seem to be of the family Diogenidae, possibly genus Dardanus> Are they safe for corals and snails? <Mmm, not very. Please read: http://www.wetwebmedia.com/hermitcrabs.htm> Thanks! Also, I included two other photos. I think it is either red slime algae or maroon coralline?  <Please read through the marine algae sections posted on WetWebMedia.com Bob Fenner> Please let me know what you think. The tank is only a month old. Adam

Hermit Crabs & Behavior (looking for a new shell or Amore?) Bob, <Anthony Calfo in your service> Quick scenario and question about Hermit Crabs. I currently have a system set up with LR, few fish, Xenia, Snails, & Hermits. I stocked the tank with just 12 Blue Legged Hermits (look identical to and I believe are Clibanarius tricolor) and 6 Left Handed Hermits (Calcinus laevimanus). Today, I noticed that one of the larger BL Hermits was literally attaching itself to another BL Hermit (this one was quite a bit smaller). It was moving its front legs and accessory feeding appendages quite a lot, but it did not appear to be outright trying to extract the smaller BL Hermit. I watched for a while, and another BL Hermit came along and was also watching. The third BL Hermit climbed onto the larger specimen, and finally I broke this up to see what would happen. The smaller BL Hermit that was being 'hassled' was then put at the other end of the tank. About four hours later, the same BL Hermit had found the smaller one - and was performing the same behavior! The same third BL Hermit found them again, and then, one by one, more BL Hermits joined until there were six all in one front corner of the tank. I thought maybe they were hungry and trying to eat the smaller BL Hermit (although, not that small), so I went against my judgment and got some frozen Mysis shrimp. However, when I returned to put it into the tank, the 'party' had somewhat broken up. I fed them anyway, and all seem to have stuck around to eat except the BL Hermit that was the focus of attention. Finally to my question: am I looking at hungry crabs, or some attempt at mating? Good Health, Ryland <hmmm... that depends...were you playing any Barry White or Luther Vandross music at the time? Er,... never mind. The behavior that you have described is not so specific as to indicate mating. They could have just as easily been trying to commandeer a shell...cheeky little monkeys, they do that all the time. When one is about to outgrow it's shell, it gets quite frisky and even tries on smaller shells (I suppose it can't tell until it puts it on!). With hermit crabs of all kinds, it is very important to always have extra and larger shells on hand. Do find and put some in...I wont be surprised if you see a shell change within a week. Do let us know. Kind regards, Anthony>

Red Legged Hermit Crabs Dear Bob, After looking over the site, you wrote about Dardanus megistos (sp?) as a type of Red Legged Hermit that controls Aiptasia. I have several "Scarlet Reef Hermits" in my 125 FOWLR and DSB. I tried a search but came up empty on the net. Are the Scarlet Reef Hermits the same? <Mmm, no... the latter are almost always Paguristes cadenati... Bob Fenner> Thank you, Jeff

Re: crabs & snails The water seems to be starting to cloud again. I was wondering if this could indeed be a population of polychaete worms as you suggested? <Possibly> and if so, how to diminish them? <Don't be overly concerned... they too shall pass in time... by predation, outcompetition for food, space...> Also, I added 100 tiny blue leg hermit crabs and 50 grazing snails to keep down the algae. (tank is 150 gallons) Could the cloudiness be attributed to increasing the bio load too quickly? <Yes> Also, are these crabs and snails herbivores? or will they need to eat more than algae? <Possibly... please try to identify them to species. Some reference materials posted on WetWebMedia.com> I love these little guys and I want to see them thrive. Thanks so much for your time. -Pat <Be chatting. Bob Fenner>

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

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.>

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>

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

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>

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>

A curiosity (Hermit Crab behavior, speculations) I don't have an aquarium or keep hermit crabs but I'm familiar with these little guys because I grew up on the Texas Gulf Coast... Rockport, TX to be exact. Many years ago a friend and I spent most of the summer at the beach. As always, we saw several hermit crabs doing what hermit crabs usually do in the surf. However, one day (I can't recall if it was late June or early July) we noticed what had to be Thousands of hermit crabs congregated in one area of the beach that was sheltered by a concrete wall and large concrete slabs so the surf was very calm. They were everywhere; some were stacked up on each other five or more crabs high. Others were just crawling about in the shallow water, frantic. But so many! Being curious, we started watching what they were all about. Well, it was amazing. I have never seen such shopping for outerwear! The hermit crabs in the shallows were trying on each other's shells. Some willingly and others not so willing. They were trying on the occasional empty shell found on the bottom or a likely piece of trash or junk floating about. Some were crawling around shell-less, having lost their shell to a rival we supposed. At this point, we made a quick trip to the closest sea shell shop and bought several 'homes' for the homeless hermits. We 'sold' all the new 'homes' and could have used more. We also experimented with the hermit crabs that were stacked up on the concrete slabs and when put in the water they were just as eager to explore a change of residence as the others. By this time it was late and we had to go to Our homes but we made plans to come back to the same spot the next morning. The next day when we arrived the hermits were gone, for the most part. And the ones that remained were not in the least interested in trying on the new shells we had brought with us that morning. Do you have any idea what was going on with these guys?  <Home shopping spree? Mmm, does seem (albeit teleologically) that there is some species survival value to such "let's change out at the same time" shell-swapping behavior... as opposed to not switching at about the same time, place... in the way of avoiding predation... and maybe some greater degree of reproductive behavior going on all the while...> It didn't seem to have anything to do with outgrowing their shells and we didn't detect any 'romantic' goings on. I would really like to know if anyone else has seen this type of behavior. Thanks. Jacki <Have noticed Hermit aggregations at times/places... and thought maybe they were coincident with food availability or tidal action... Don't know... but perhaps others will chime in with the posting of your note on the Daily FAQs: http://www.wetwebmedia.com/dailyq&a.htm tomorrow. Bob Fenner>

Hawaiian Hermit Crabs (John.H Book) Hallo, <Gutentag> I am looking for the book 'Hawaiian Hermit Crabs by John Hoover, 1997. I, II. FAMA 9, 10/97. Where can I buy it in Hamburg, Germany, und how much does it cost? <I will send your request to Sue Steele at FAMA and ask her to respond. They can likely send this work to you easiest.> Thanks and regards Cornelia Warneke-Cremer <Wiedersen. Bob Fenner>

Anemone hermits I think I have a pair of anemone hermits in my tank. They came in with the blue legs at my LFS, and I thought they were cool so I bought them. They are black and white and larger then my blue legs, the largest being the dominant and the small just pushes everybody around, or runs over them without a care. I have a book on hermits, though it's a bit dated, and it mentions the black and white legs as being indicative of an anemone hermit. I love my little hermits, they are fun to watch, but these two seem to have a problem, they came without anemones. I have watched the largest rub up against my "flower anemone" (no idea what it really is) several times and poke it to close so he could attach it. Well the anemone is about 4 or 5 inches in diameter and the hermit shell and all is only about 1/2 an inch. I think that the loss of my smallest Condylactis anemone was due to the same treatment, he'd already been abused by the biggest anemone earlier. So I guess my question is do I really have anemone hermits, what kind of anemone do they need, and how do I acquire the proper species of anemone.  <Hmm, can't tell the species of Hermit from the description. Please take a look at the few species shown on our scant coverage: http://wetwebmedia.com/hermitcrabs.htm And maybe search the internet through your search engines under the names by genera of hermits... And ask your livestock suppliers to look for live rock, other hard based organisms from the region of origin of your Hermits to see if they can find "recruits" (contaminant) anemones on these> How long before they get to big for a 60 gal FOWLR (with a few inverts on the side) tank.  <Maybe weeks, months... perhaps never> I have some dragonets and I have heard that hermits have a taste for these cute little fish (my friend lost her mandarin to a large hermit) <They have more cosmopolitan tastes... eating most anything they can grab> like I said earlier, they are pretty small, but since I got them a couple of months ago they have shed once and changed shells numerous times (there are a lot of shells in there and apparently they have to try them all!!) Thank you for all your help once again. Kim <Enjoy these animals... keep them well fed... and keep an eye on them! Bob Fenner>

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 toooo opportunistic/predacious)?  <The "blue": Clibanarius tricolor... image, more on the WWM site under Hermit Crabs.> I kinda 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 gotta 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>
Re: Clean up crew (and WWM help)
Hi Bob, That's very nice of you, but I don't consider myself in the same league as either you or Zo when it comes to knowledge of aquarium husbandry (Well, of course not! You've been in this industry for over 30+ years!?). The last thing I would want to do is to give someone bad advice and cause them or their fishy friends any suffering. That said, I'd love to give back to the hobby and assist you if I can. Let me know how I can help. Khoi <You do help my friend, and know perhaps much more than you're aware. It is not necessary to be knowledgeable about everything to be of service. As important as useful input is compassion (Latin: "to bear pain with"), apathy/empathy, a genuine desire to assist others. There are reference works, others that can/should be referred to. Consider this. Bob Fenner> Re: Clean up crew (and WWM help) Good morning Bob, Ahhhh, I see you're out diving and Zo is manning the boards! OK, if I can help out you and Zo with some of these questions, I'd be willing to give it a try. Khoi <Outstanding. Will email him this missal. 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 crabs hello there Robert, I would like to know If It is possible to keep cold water hermit crabs permanently in a tropical reef set up. I stay on the west coast of Scotland where I would be collecting my specimens. I have a 50 gallon tank with various soft corals. <Hmm, well, sometimes these cold water non-vertebrate animals will "make the switch" to a degree collected during the warm months of the year... And species that are intertidal are pretty eurythermal... About the only way to tell my friend is to collect and try some out. Bob Fenner>

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

Hermit crabs Hi Mr. Fenner. I have another question once again. Do hermit crabs also molt, or not since they keep looking for bigger shells?  <They do indeed molt> I ask this because if they don't molt, then I have something going on in my aquarium that might sound strange. I have six red legged hermits, and two that are very dark, almost black. I've had them for months, and every so often I find what looks like the remains of one of them. I say remains because it looks like they have been eaten, and all that is left is the front part, like the head, and legs. sometimes the remains are red, and other times they are dark, which shows that both types that I have are doing this. It's not a clear shell like when my different types of shrimp molt, but actually looks like the remains of the body. Yet when I take a roll call, all of my hermit crabs are still alive, and well. <Good observations, relating... No worries... keep supplying a selection of "new homes/shells" to move in to. Bob Fenner> Thanks Greg.

Hermit Homes, Aiptasia Mr. Fenner First Off I would like to say I really like your book I have found it useful in so many situations.
<Ah, deeply gratifying to hear/read. Thank you> I have several questions. One Is: In your book you say that Nudibranchs are not suited for home aquariums because not much is known about there feeding. But recently I have been seeing many ads for lettuce Nudibranchs. They say they take care of hair algae. Do These really work or is it just a gimmick. <Mmm, these are not really Nudibranch species... They can work. Not so specific in foods (algae) that are taken...> Another do blue leg hermits and scarlet hermits outgrow their shells. <Yes> If so how often do they need new ones and how much bigger should they be.  <Provide several of varying sizes and let them choose> What happens if they don't get them. <Not a pretty story. Get larger, no where to move, get eaten by their fellows, other species> Lastly in my reef tank there is this "thing" attached to my live rock. it's hidden by a small pile of rock about a cm. high) and it has several hair-like, very thin, tentacles about 3-5in.) that reach out into my tank's gravel and pulls up stuff from the gravel. Do u know what this is?  <Sounds like a Glass Anemone/Aiptasia... read about them on the WWM site> Does it sting?  <Yes> It seems to put out a lot of waste it excretes it all at once and it seems to be a lot for how small it is <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

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>

Rock hermits Hi Bob, I have kept a Dardanus deformis rock hermit (complete with his anemones) for several months now. I love this guy, of course he is in a FOWLR system. He has shed twice, and both he and his anemones have grown substantially. He is currently in about a 2" shell. I have seen him sit his anemones down on food pellets ( coincidence or what ??).  <Not coincidence... purposeful feeding of mutualistic symbionts> He is so much fun, but I can't find anyone else who has or has had one. Here's a pic, but he's bigger now. http://www.members.home.net/d.hadford/rockcrab.html Deb Hadford <Very nice... do see this species in the trade occasionally... easily collected at night. 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


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

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

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

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>

Further: 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>

Staghorn Hermits Hi Bob, First off GREAT BOOK! The Conscientious Marine Aquarist) Its one of the best ones I have read. I have loaned it to all my fish loving friends. Now for my question, I saw that FFExpress is selling Staghorn Hermits, I was just wondering a few things about these wonderful looking crabs, I can not find ant info on them. Are they reef safe? What do they eat? Does the Staghorn grow with them? Does the actual Staghorn have any special requirements? Where do the come from? Please Help! Thank you. >> Hmm, I'm down to my last/only copy of CMA as well... The Hermit you mention is probably a member of the genus Manucomplanus... also called the Coral house Hermits... they're relatively reef safe, getting along with the vast majority of invertebrates... As hermits go they're more secretive, don't care for bright lighting... and require higher water quality than the bulk of the hermits. Most come out of the Pacific, but there are similar looking species elsewhere. Bob Fenner

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 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 algae... Bob Fenner

 Hermits I have a small question about my skimmer less Berlin 29 gallon reef system. I know that I am limited in my live stock however, are red leg or left hand hermit crabs considered when it comes to having too much livestock in my tank? I plan on adding about 20-25 of them. right nor I just have a leather coral about a 6 inch mushroom rock and 6 inch button polyps. I do have other reef tanks, but never a Berlin. thank you for your time. Ted >> Nah, not much Ted. They come and they go, w/o much fanfare or consequence. Just keep an eye that none are bugging your corals much. Bob Fenner

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>  

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