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 zooeal 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 wanna 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
<please do take pics and document this if you can. I'd love to see them and many others too if you will give permission to us to post the images. Thanks kindly, Anthony>