HCA: Hermit Crab Association

Hello I am new here and I have a question about hermit crab behavior, I hope I am posting this in the right place/way. I looked around and I’ve seen a few people asking similar questions but many posts seemed specific to the original poster’s situation, so I apologize if this is something that gets asked a lot/has been addressed and I missed it.

I got two smallish PPs about a week and a half ago and with the help of much research and many threads here I’ve set up a nice crabitat with all of the basics (as far as I know) with >80% humidity, temp ~75-82, lots of hiding space, lots of substrate in 20 gallons.

Both crabs seem okay, they climb frequently and I hear them bumping into the glass at night, I also know that they’re eating regularly and drinking now and then.

I am a little confused about their general behavior though. When I placed them in the tank they stopped hiding in their shells and from that point on neither of them has really packed themself back into their shell all of the way. They both changed to larger shells as well and still when they’re hanging out around the tank resting they both kind of just sit either peeking out or with their legs/claws out like they would if they were walking/eating. Do people find that this is normal? I thought it was okay, but I read that a crab hanging out of its shell can mean that they’re unwell. These guys don’t seem to have any mites or anything and they are pretty active in terms of climbing and for one of them digging as well. Do people see their crabs resting like this just partway out of their shells usually? Or do they actually like to pack themselves into their shells and seal the opening to rest? They seem like they’re just kind of relaxing but now I’m nervous since I have been having a little trouble keeping the tank temperature up.

I adore these little guys and I’d like to see them both make it past their first molt, but I’m not sure what counts as a crab hanging out of its shell.

This sounds very normal! Every crab is a little different in how they like to rest and what is okay for one can potentially be a warning sign in another. I realize that isn't helpful in the moment, but there are times when I still get scared for no reason when I glance over and one is sitting funny.

When talking about hanging out of a shell though, they really do mean hanging and limp out of the shell, to where the start of the abdomen is exposed at the top. Usually, and I hate having to use generalities but again they are all a little different, when a crab is that exposed they tend to be very weak and having trouble supporting themselves and the shell. However, they will sometimes hang this far out when bathing themselves or if they are carrying eggs, but it will be brief and their antenna stay active.

Sealing up completely tight is a defense mechanism when they are frightened. They really shouldn't do that unless they get startled for some reason. It's common for new crabs who are still settling in, or if they get disturbed for some reason. Sitting closed up with just the leg tips out can be a comfortable position for some to rest, but it can also signal that they feel a little too exposed.

Thank you! I didn’t realize that when looking for crabs hanging out of their shells I should be checking for general signs of weakness too but that makes a lot of sense now that you say it. I think your explanation gives me a better idea of what to look for if they’re very unwell which hopefully I won't see, but it’s comforting to have more info. It’s also good to know that they don’t always like to be tucked inside of their shells. I just wasn’t sure.

Based on this, I think my guys are definitely just resting, especially since they like to rest on top of things and they must need strength to get up there

Oh yeah, its all good! I got a crabby who sleeps upside-down! Congrats!

Hermiecrab wrote: ↑

Thu Oct 28, 2021 3:48 pm

Oh yeah, its all good! I got a crabby who sleeps upside-down! Congrats!

Bat-Crab!

Hermiecrab wrote: ↑

Thu Oct 28, 2021 3:48 pm

Oh yeah, its all good! I got a crabby who sleeps upside-down! Congrats!

Lol that's hilarious! Thanks! This all makes me feel much better. They are such bizarre little creatures, I wonder what they’re thinking when they climb around.