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FAQs about Hermit Crab Reproduction

Related Articles: Hermit Crabs, Crabs, Marine ScavengersFresh 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 Disease/Health,
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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,

Hermit crab spawning?  9/1/11
Good morning, crew, I've got my third question in two days for you now (I think I'm going for my personal record).
Yesterday upon returning home from work, I walked over to feed my tank and witnessed one of my red legged hermits outside of its shell and investigating a shell that looked distinctly too small for it (as I didn't watch it evacuate its home, I can't tell if this is its previous shell). I found this odd for three reasons: 1) everything I've observed and read suggested that hermits usually relocate at night; 2) my other hermits, which have proven to be particularly opportunistic in the past, waltzed right by and left this exposed one alone; and 3) there were several larger, and in my eyes better-suited shells close by, but this crab didn't seem at all interested.
<Mmm... very dangerous to be outside their shells>
Well, needless to say, I took a knee and began to watch the crab closely, when I observed a feathery brown patch stuck to its soft bottom half. Upon closer inspection, the mass appeared to be dozens of little orbs with small flecks of black inside them. I'm assuming this is a clutch of eggs, so I was curious about this particular species reproducing in home
<Does happen>
Like I said, I found it odd that the other crabs (as well as my peppermint and cleaner shrimp) left it alone all together. I wouldn't mind having some new inhabitants, as a friend of mine is in the process of setting up a 75 gallon tank and could use a cleaning crew, so if it is indeed spawning, what can I do to assist?
<In two words, "not much"... These anomurans "come" in a variety of larval development phases... but all require quite a bit of planktonic fare for food>
There is plenty of live rockwork and crevices for safety, but the underside of my rock (supported by an egg crate cutout), has become the mini mansion to my Randall's pistol shrimp, and I thought he'd have a go at the young for some additional food.
<Very common. I know of no successful accounts of Hermit rearing in captive/aquarium settings.>
Also, since hermits don't grow their own shells, how big will the young usually be before looking for their own home, and how small of shells will I need to accommodate them?
<Mmm, very small indeed... likely there is some beach area that has a mix of such as part of its component...>
<And you, BobF>
Re: hermit crab spawning?    9/2/11

Thanks, Bob. I had sort of assumed that was the case with the crab spawning, but thought it'd be nice to help a friend save a few bucks with setting up his cleaning crew. On the bright side, at least I don't have to worry about my tank getting accidentally overrun with a hermit army (just thinking about it gives me nightmarish visions).
<I see; again, not to worry>
Oh, one more quick question for today. To better house my anemone and its clones, I'm constantly on the lookout for a used tank larger than what I have. Well I found one in the local classified ads, and it's an 80 gallon corner tank with a pre-drilled overflow (fortuitous, as that'll save us some space along the wall). There are no chips or cracks in the glass, but it does have (as described) as "slight leak" around the front bottom right seal. I know that irregularly shaped tanks can provide certain challenges, so is there anything extra I should consider before attempting a repair, or should stripping off the old sealant and reapplying suffice?
<While I was at it, I'd add some internal bottom inside strips or glass doweling. Read here re:
Hope all is going well in Fiji,
<Yes; but up at one, two, and now three AM with many dogs barking... but had to be up at four to get back on out to Vatua Reef... Not looking forward to the boat rides. Cheers, BobF>
Re: hermit crab spawning? Aq. repair     9/2/11

Thanks, Bob, I'll definitely brace the tank when resealing it. This is new territory for me, but luckily I'm fortunate enough to have a friend working as a glass cutter/installer.
<Ahh, fortuitous>
Finding as I get older that having a lot of skilled, blue-collar buddies really pays off...though maybe having
a generous rich friend would help fund this expensive hobby :p
<Cheers, BobF>

hermit crabs, repro.!
I enjoyed your answer to the questions about hermit crabs mating. We have the red legged crabs and evidently missed the whole mating thing and now have a hundred?? baby hermit crabs in our 50 gallon tank, do we need to do anything for them?
<Mmm, yes. Feed them... keep potential predators away...>
Will they get eaten by the other crabs or fish?
They seem to be trying to get out of the tank?
<What they do... are not totally aquatic... More amphibious>
Any info you can give would be helpful. Thanks
<Welcome. Bob Fenner>
Re: hermit crabs, repro.  08/23/09

What do you feed such tiny little crabs? Is there a mini food or what?
<Small foods of many sorts will suffice. Scan the Net re Anomuran culture.

Hermit Crab Spawning 12/01/08 Hi Guys and Gals, <Hola> Just wanted to share an experience that may be of interest. I've been reefkeeping for about 5 years now and recently have discovered that it is not just my Ocellaris clowns that are comfortable in their little glass box (75Gal). The other night after lights out, I needed to turn the light on to check something in the tank, and amongst the confused fish life I noticed hundreds of tiny little fry swimming in the water, and milling about on the substrate. At first I thought my Clown eggs had hatched, but they were all still safely attached to their rock. It wasn't until last night (for the second time) I that amid a sea of these little white spec's (not pods) I noticed a hermit crab lying on its side with wave after wave of tiny fry swimming from its shell (I posted a vid on YouTube http://au.youtube.com/watch?v=uwiMlOQUjZ0). <Neat!> From what I've heard, hermits don't often breed in home aquaria, but I've had these guys for about 8 months now, and have grown them from tiny pea sized crabs to what are now (about 4 times that size), and I'm pleased that they consider something I've created a suitable environment to breed in!! Though I'm sure my mandarin is even more excited about it =) I hope this is of some use to you, feel free to link to the vid if you find it of interest. <It is definitely interesting... thanks for sharing with us!> Take care. Andrew B. <Thank you, Sara M.>

Can I raise baby hermits? 1/5/07 Ok < Graham with you tonight.> I've searched and searched but still can't find out what I'm supposed to feed 1 thousand baby red legs / hermits! < http://www.wetwebmedia.com/hermitreprofaqs.htm > Yes this is the first time I've emailed before , I'm only 13! <Awesome! Good to have some young blood in the hobby.> So exactly what do I need to do with 4 soon to be mother hermit crabs? how long does it take for the once hatched babies to even start looking like their parents instead of shrimp / hermit crab? What do I feed them and how? <Try Google-ing on this site only, and see what you come up with.> I have two reef tanks: a 55 gal and a 20 gal. The 55 acrylic has 1 male Yellow Sailfin Tang who does not like my dad, two Black Ocellaris clownfish 1 male and one evil female who means murder every time my hand or anything else besides the bubble tip is in the tank or is put into the tank!! One 4 inch Mithrax <You mean Mithrax, like the crabs?> -male , 2-inch female , and  a 1- inch female. Tons of clams, long story short it's a true reef, but without problems!! <Good to hear. Not often do I read that.> We even lost power for FIVE DAYS , AND NOTHING BUT THE CLEANER SHRIMP DIED , crushed by a falling rock !! <Aww...> Ahh the evil clownfish and male Mithrax + the Tang are having war, came a little to close to the host !! Got to go!!!!!!!!!!!! <Good to hear from you, hehe. Spread peace! (...Mithrax???) -Graham T. >

Infant Hermits? 10/10/2006 Aloha Bob, <<Hey, this is Lisa :D>> Perhaps you could shed some light on this mystery for me. <<I shall try!>> I have a 50 gallon salt water reef tank.  Fish and 3 Hawaiian red legged hermits are the only creatures in it.  One of the hermits was hanging out on a patch of algae for most of yesterday.  This morning when I fed the fish, I noticed some (a hundred?) tiny white dots on the same patch of algae.  Upon further inspection, these tiny white specks are mobile, and slowly moving all around on the algae.  Are these baby hermits? <<Nope, they’re ‘pods.>> If so, how do I help them live to adulthood? I always thought they wouldn't reproduce in a tank. <<’Pods require no intervention on your part.>> Thanks for any info or advice you may have in this area. Mahalo! <<Not crabs, but a nice addition to the bio-diversity in your tank!>> Sheila (surprise crab mommy) <<Lisa.>>

Tiny hermits making an appearance.... Hello WWM Crew, Always appreciate you as the best resource on-line!  Maybe you can help me solve a recent mystery in my 200 gallon set-up. I've had 4 Halloween hermits in residence for the past two years, all seem to be doing well. Last night while I was cleaning the substrate I counted 14 tiny hermits amid the crushed coral? <I'll bet your counting is fine... now, put your shoes back on!> All are in tiny shells and were going about their business. The last fish addition to the tank was over 6 months ago and we haven't changed the substrate or added any additional live rock for over 18 months. Where the heck did all these little hermits come from?  <Well, you have a mommy hermit, and a daddy... Could be from your existing stock or recruits from the LR> If I could count 14, there are probably more that I couldn't see in there... Any Ideas? Elizabeth Turner <Visions of that large yacht are dancing through my proximal lobes... Actually, enjoy, trade them to others, the LFS's in your area if they seem to be getting too populous, scavenging too much. Bob Fenner> 
Re: tiny hermits making an appearance....
A marine guru and a comic, information and entertainment, no wonder I return time and again. <Heee, heeeee, if I had any timing I'd give stand up a go> After reading through many of the faq's it didn't seem likely that the offspring of the "mommy hermit and daddy hermit" would have survived as anything other than tasty tidbits to this stage so that's why I was somewhat perplexed. <Mmm, does happen... these anomurans have a few reproductive strategies... not always planktonic larval stages> Nonetheless I'm pleased to have some homegrown, they will make good additions to our "soon to be cycling" 1000 gal built-in set up that the contractor promises will be ready for water and live rock next week ('cept I've been hearing that for 6 weeks). <Wowzah! Now... that's a tank!> If Adam West (batfish) and the rest of the crew haven't munched them till now, they might just survive :) Thanks Bob Fenner! Elizabeth Turner <Welcome. BobF> 

Reef Hermit Crab Reproduction 10/20/04 Hello Bob, <Anthony Calfo in his stead> I'm fish sitting.  Of the eleven tanks here, only one is salt water.  It is a relatively new 100 gallon set-up.  About three weeks ago, the owner bought a large hermit crab that is orange with raised black bumps and the bumps have white spots. It appears as if there are two similarly colored, yet smaller items buried in the corner of the tank.  She (I assume) has buried food also.  She stands in this corner now where even just days ago she was all over this large tank.  Are these babies? How?  The owner said she was the only one in the tank when he purchased it.  He thinks she has shed a buried the shed.  Is this what has happened?  What is happening? Thank you for advice and guidance, Jennifer C. <I agree... it sounds like a shed exoskeleton - they are remarkably complete and look like the "real thing". Reproduction in hermit crabs is complex and rarely successful in aquaria... often involving the juveniles being carried inside the parent's shell upon their "backs" for some days before being released into a tank that likely has no shells of correct size for the tiny babies and, as such, they perish in hours/days. Anthony>

Reef Hermit Crab Reproduction question Hi Anthony (in Bob's stead), <howdy again> Any answers for me?   <Ahhh... any questions for me since my last response to you?> The hermit crab (orange with black lumps, white dots and orange hair like projections) is still standing in the corner of the tank.   <still thinking it could be a molt since you have not mentioned any movement... or anything in fact other than "still standing"> From what can be seen through the gravel in the corner, it appears to be a baby (or babies).   <wishing for a teleporter at this moment> The owner confirmed that she was added to his 100 gal. (relatively new) salt water aquarium about four weeks ago now. What should I do?   <tough for me to say with no pic and no more information that "standing in a corner"> Do you know of successful crab breeding in captivity? <yes... as described in last e-mail. Rearing is the challenge> Besides buying some shells (done) <huh? babies are literally a 1/16th of an inch in size or a whisker larger. I cannot fathom where one would get shells this small> and seeing that food makes it to her corner (done), what else needs doing?  How long will this progression take?  What is happening?  How long has this been going on? <we have so information to go on here. You are asking us to guess blindly, dear> Thank you for any answers.  I'm watching this place while the owner is out of town.  Salt water tank responsibilities are a bit more than I'm used to and this situation has added a new dynamic. Jennifer <hmmm... sorry to be flip in my response above, but please do consider all/what you are asking when we have no image, sizes, description or anything else to go on here my friend. I don't see what I can do for you :( You need a closer look and a very clear photo to go from here. Anthony>

Reef Hermit Crab Reproduction III 10/27/04 Hi Anthony, Sadly, the baby died.   <ah... very sorry to hear it> The mother crab used it's pointy leg to lift the single baby crab out of the sand / gravel.  Apparently the soft fleshy part had been feasted upon by one of the tank mates. The baby (now in the freezer) has a body a little larger than a quarter (about half the mother's size).   The legs are about the size of a pinky, though a smaller diameter. <too large to actually have been a baby. Somehow, with rock, ornaments, shells, etc... a small adult crab (with or without shell) made its way into your aquarium. For how slow these crabs grow... there is no way this was a baby born in aquaria> We watched through the gravel as the shell grew little orange hairs.  Both my  daughter and I were sad that we could not protect the little crab.  The  mother has returned to traveling the tank and spending much time perched atop the coral. How can I find out what type of crab we have?   <begin with general keyword/phrase searches on google.com for hermit crab species... and see if you don't recognize some genera like yours to refine a search> You had said babies were minute.   <very true> Is the larger offspring specific to some breeds?   <not that large... physically impossible> How did the mother transport the egg, larvae or whatever a crab embryo is called into the tank?   <could have been a small male that left its shell to mate and got carried/sold with your female in shell> How long do you think the progeny was deposited under the gravel? <I am as certain as I can be that this was in no way, shape or form a baby of any kind> I don't have a digital camera.  I did, however, take 35 mm photos.  If you would like I will scan them and email them to you.  I'm sorry I was unable to get them to you previously. Thank you for all your help. Jennifer <best of luck! Anthony>

Hermit crab self propagation? My son brought home a hermit crab from the beach at cape cod, ma. It went into a small aquarium alone. Over a year later I found it dead outside the shell.
<< That is actually quite a while to keep one.  I don't think anyone here recommends you collect a hermit, because it almost always turns out with a quick death. >> I went to clean out the little tank and dispose of the shell when to my surprise, there was another living crab in the shell that was obviously very new to the world. How did this happen? << Well I only have a partial answer.  Hermits don't grow their own shells.  They simply crawl out of their shell and into a bigger shell as they grow.  So that is why you find them without shells.  It is also why it is important to have many shells of all different sizes in a tank with hermits.  Once out of their shell they are very vulnerable and need to find another quickly.  As for how there is a second youngster in there.... I have no idea. >> Thank You, Linda <<  Blundell  >>

Marine Hermit crab reproduction methods - 7/28/03 Hello WWM Crew,<Hello there. Paul Mansur here today> I'm a long time reader and fan of the site. <Fantastic. Glad to hear> This is my first time writing (because the site is so darn comprehensive and all my other questions have been answered before!). I have 2 scarlet reef hermits in my 10g Nano and just want to know if they are hermaphrodites or distinctly male or female. My guess is the former, but their behavior makes me wonder. I think I have seen them mating. They both went down into a big, secluded hole in the live rock and faced each other and sort of interlocked legs and came partially out of their shells so the soft parts were exposed. One crab is much larger and more aggressive and was dominant during this "interaction". The smaller more passive crab is the one I later saw releasing tiny larvae at night (I was shining a flashlight on it). They have spawned a couple times already. I can't seem to find an answer about if they are dioecious or hermaphrodite in my books (I have books by Fenner, Delbeek and Sprung, Tullock, et al). I know this isn't of earth shattering importance, but I was just curious. Thanks in advance! -Ken <Well Ken. I think I have an answer for you but it is based on California species (roughly applies to tropical species as well). This is the answer I personally received today from an associate of mine Dr. Robert Toonen Assistant Research Professor, University of Hawaii at Manoa School of Ocean and Earth Science and Technology, The Hawai'i Institute of Marine Biology I hope this helps. It does correlate with your findings: "There is quite a bit of variability among different hermit crabs in their mating behavior, but I'll try to give you some reasonable generalizations. At least the larvae are relatively easy to raise by comparison to most inverts.  I've never raised any of the popular aquarium species (like blue- or red-legs), but I've raised several of the local CA species.  With one exception, all the hermit crab species with which I am familiar brood their larvae externally (but within the shell) until they complete the nauplius stages (early stage larvae, similar to a baby brine shrimp), this period can vary between about 1 and 12 months, depending on the species.  The females then release either zoea or megalopae (just fancy words for more-and-more mature larval stages) which typically feed on phyto- and zooplankton.  Depending on the species, this planktonic larval stage can last days to months.  Because the youngest stages are brooded within the shell, and because rearing of the later-stage larvae is relatively simple by comparison, hermits are a good choice for an attempt at breeding tank critters at home."          "Hermits have separate sexes with relatively little sexual dimorphism.  The best I can offer is that, in general, the males tend to be larger than the females and in some species the chelipeds (claws) are larger on the males.  Hermits often have elaborate mating behaviors (displays, shell knocking and such) during which the male will guard the female until she releases the prior brood that she is carrying.  Thus, in the aquarium, when people see this, they report a larger hermit "messing" with a smaller one, and suddenly the smaller one sprays out a stream of larvae.  Once the brood is released, the female typically molts prior to copulation (which is why the male guards her) and extruding their next brood.  During copulation, the male attaches dozens to hundreds of spermatophores (packets of sperm) to the "abdomen" of the female, and eggs are fertilized as the female releases them prior to attachment to the "abdomen."  The male then moves on (this "courting" period can take anywhere from several hours to a week or more in some species), and the female then carries a colorful brood of fertilized eggs on her "abdomen" (or more correctly on the pleopods) within the shell for anywhere from several weeks to a year or so, during which time she constantly cleans and ventilates the developing young."          "The larval duration depends on the stage at which the brooded larvae are released.  The larvae typically go through something like 1 prezoeal stage, 4 zoeal stages, 1 megalopal stage and a final decapodid stage of development before becoming a tiny "adult" (although this again varies by species).  In most species, the prezoea and some variable number of zoeal stages are completed while the mother broods the young, until they are released (usually around 2 mm in length) and the planktonic larvae spend something like 20-90 days as a feeding larvae before molting into the decapodid stage (which is capable of both planktonic and benthic life). During this time the larvae feed on phytoplankton but usually prefer small zooplankters (such as rotifers, ciliates and the larvae of other invertebrates) when they can get them.  There are some exceptions in which the larvae are nonfeeding, and spend a relatively short time in the plankton (several days to a week or two), but these cases are relatively rare compared to the number of species that produce the feeding stages, and I don't know of any tropical examples of this off the top of my head. So, if you want to raise hermits for a reef aquarium, chances are good that you'll have some intermediate- to late stage larvae released by the brooding parent, and will have to feed them until they complete their development...Hope that helps...Rob" By the way, this is from an email to me, Paul Mansur, personally and no reproduction other than the use of it by WetWebMedia is acceptable. Expressed written consent is necessary for its duplication by Rob Toonen. Thanks for your understanding.

Hermit Crab babies? 1/23/04 Hi, the research we have done says that hermit crabs do not mate in captivity.   <it is uncommon... and commercially not a viable product for how inexpensive and plentiful they re to collect> We have dozens of what appears to be baby salt water hermit crabs.  Is this possible? <yes... I do have a photo series from a friend who recorded it in his tank. Surely at least a few if not many other instances of it have occurred for others.> If so, our shrimp are eating them.   <yes... and many other inverts and fish in your tank would love to as well> Any suggestions on how to keep them alive? <keeping the breeding hermits in a safe refugium might help, but the best way of course would be in separate aquaria. DO look to the old classic marine aquarium reference "Beginner to Breeder" by Martin More for general info on husbandry and system techniques and hardware. And there is much data abroad on rearing shrimp which will be somewhat helpful for your attempts here> Thank you, Kandi and Rich

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