Celebes Jungle Crabs

[Mustafa]

I started out with 18 crabs (only 5 females) and about a month later I have about 6-7 left (with one female if I am not mistaken). It's hard to say when the dying stops. Since they go through a lot of phycsical (capture, transport etc.), chemical (mainly ammonia, stress hormones etc.) and biological (bacterial blooms, infections) stress before they actually end up in our care (catching, transport to holding containers, transport to exporter, transport to importer, possibly transport to wholesaler, possibly transport to a store, finally end up with hobbyists) it's really difficult to determine how long an individual crab will survive. Sometimes the stress is less, sometimes more. What I have found out over many years of observing imported inverts is that tthe stress seems to be cumulative. In other words, even if an animal "recovers", starts eating normally and looks (almost) just fine, some relatively minor additional stress can kill it. That's why captive-bred animals are so much more robust. That's also why it's relatively hard to establish captive populations of wild-caught species, as one is racing against time to get the animals to breed before most of them die away.

So..let's wait and see. As for a registry...I don't think that's needed at this point as there are only a handful people who are actually trying to breed Geosesarma anyway. What I can do is create a separate "Crabs" section in this forum so all the posts are in one place.

[Guba]

When I found the male he was missing a claw. I'm taking a guess here that maybe (fingers crossed) he tried to mate with the female that molted?? Thanks Mustafa, for the "cumulative stress theory", it kind of reinforces all of my experience with shrimp and crays. I can see where it could apply to crabs too. Sorry to hear of your losses on such a big scale though. OOCH!! I think a crab forum section would be great!

[Guba]

Okay, so last week I thought I lost one of the females. Today the other female wasn't in her hiding spot, so I took the tank cover off to start looking. What I found were two females! I assumed the one crab died because the molt had so much color in it, though not as much as a living crab. Now I wish I had the old molt so I could examine it more closely. Crab molts, at least for this species, can be colorful. Still on a learning curve here!

[Mustafa]

The molt for Geosesarma is about the same color as the animal itself. That's the case with my orange Geosesarma sp., too.

[Guba]

How are your crabs doing Mustafa? Are you having any luck/skill/accidents with your crabs?

[Mustafa]

I have one pair left right now. The male killed off the other males one by one (tore off their legs and claws which did them in). Looks like this species (and probably other Geosesarma spp.) become territorial at least during mating time (and maybe even at all other times). That would mean that one can't keep these guys colony style. The male and the female literally paired off and are living in the same hideout. I only see glimpses of the female so I don't know if she is carrying any eggs. If anything happens I'll let everyone know.

[Guba]

Thats intresting info! Hope you do have a pair. This morning I found one of my females inside my fruitfly culture. The odd thing about that is that she could only get into it by jumping from a nearby limb. I've witnessed one time were a crab jumped from my hand, so I think it was totally within her capability.

[Guba]

Yesterday I discovered the other female molted, finally. This female dug a pit that goes down to the water level, but what was left of the molt was up on top of the substrate. It looked as if she molted on dry land as opposed to all previous molts which occurred in the water.

[Mustafa]

I've seen molts happen mostly on dry land although I have seen the exceptional water molt, too. My pair of "mandarin crabs" live in a cave that they dug under their large water bowl "swimming pool." It has two entrances, one where the female hangs out and another where the male hangs out. Interesting... Still no eggs, though.

[Guba]

Today while cleaning the tank I discovered 3 juveniles with a carapace diameter of about 6mm. I saw a fourth one with one of the females that was only about 3mm in diameter. Their coloration blends in with the gravel really good. The only way I noticed was because I saw a knot on the branch moving away from my hand. The one female that I could remove I put in a plastic container and checked to make sure it was a female or if maybe it changed sex the way some species of fish do, but it's still a female. The male died four months ago. Now I'm going to have to pay more attention to the size and as they get older I'll put them into other quarters. Hopefully I'll end up with a male and female.

[shrimpthing]

Great job! Here's hoping for more babies!

[Guba]

Well another update! I still have one of my original females. However I lost one of the 4 juvenials, which are now adult size. But today I discovered a 3rd generation!!! Carapace diameter is probably 2-3mm. With lessons learned I'm going to start another tank and spread them out. I don't like keeping all my eggs in one basket.

On a sad note I just discovered that the smaller of the 2nd generation has passed away. Seems like every step forward has a small step back.

[Mustafa]

Update on Mandarin Crabs: I have young from 3 different broods running around. My male died a few weeks ago, female died 4 days ago. The young are growing extremely slow. First young are from January and they still have not reached adult size. We'll see how long they take....they are still living extremely hidden.

[Guba]

Sorry to hear about the loss. It was about a year before the first of my brood took on the adult coloration. I'm still not sure how long the female carries the eggs/hatchlings.

Are you keeping all the crabs in the same tank? Have you noticed any cannibalism?

[Mustafa]

Yep..they're all in the same container. I did not notice any cannibalism, but as they live a very hidden life I can't rule out the possibility. My crabs actually take care of their young for a while. The breeding pair used to live together in a hole they dug. After the young hatched the mother would carry them around on her back for a quite a while, similar to some scorpions. Even after the young "got off her back" and moved around on their own, they would stay in the whole for a while before venturing out on their own (and digging tiny holes for themselves). This piggybacking behavior seems to be, so far, unique to this species (mandarin crab), so you won't see the same behavior in your crabs.