Hermit Crab Nightmare: My First Surface Moult

I suppose I should admit something to those of you who don’t know: I have hermit crabs. Now, I don’t think I would ever recommend hermit crabs as pets because they’re quite high-maintenance and stressful exotic animals to keep (albeit, my little guys have brought a unique joy to my life). One of the very stressful aspects of owning a hermit crab is the process of moulting.

In order to get bigger, all crustaceans have to shed their hard exoskeleton in a process called moulting. It’s a stressful period for a crustacean due to hormones, lack of food, and the vulnerability of having a temporarily soft exoskeleton. A hermit crab that is preparing to moult will dig itself underground where it is a lot less susceptible to harm. However, hermit crabs – who are usually social animals by nature – have a reputation for digging up other moulting crabs to steal their shell or cannibalize them.

I’ve had this happen to me once in the past; one of my first hermit crabs was ripped to shreds because another crab wanted her shell. I’ve since had at least 8 successful moults and very healthy crabs, but I’ve always been paranoid that it would happen again. It did.

This is my hermit crab, Ghost (aka Baby Jesus), after being dug up and ripped out of her shell just as she was preparing to moult. When I first found her she was lying limp and naked in the soil. The culprit, Berri, was sizing up the shell she had stolen. To deal with the situation, I removed Berri from the tank and placed the stolen shell close to Ghost. I hoped she would crawl back into her shell, but she would only move and squirm if I had my hands inside the tank. It seemed as though she couldn’t move the legs on one side of her body. I was afraid she was in really rough shape because of the attack.

An hour later she still hadn’t gotten back in her old shell, so I placed her in a smaller emergency tank where she would be safe from danger. She wasn’t moving that much and I was afraid I would lose her overnight.

I woke up in the morning and checked on her right away. It didn’t look good; her body had gone completely limp except some movement in her exposed abdomen. To me, it looked as though she was writhing in pain. I had to leave to go to work, but I thought about poor Ghost all day. I dreaded going home to check on her. I was terrified I’d find her dead.

Instead, I found this when I came home:

That, my friends, is the pink and fragile body of a moulted hermit crab. She was moulting all along! That explains why she looked limp and dead earlier in the day. However, I noticed she had some issues with her legs: her old exoskeleton was still attached to her body on her big pincher and on one of her legs. Interestingly, these complications were on the same side of her body that she couldn’t move earlier: likely a result of the attack. She wasn’t out of trouble yet, since this added to the stress of her moult and likely meant she’d end up losing those legs.

I left Ghost to rest for several days, disturbing her only once in the morning and at night when I’d mist the tank with water. As expected, she lost her large pincher. However, she did manage to get the exoskeleton off her leg, which prevented her from losing it.

I’m happy to say that she’s fortunately made a full recovery. Without her large pincher she’s got a higher risk of being hurt by other crabs, but I’d rather not isolate her and instead will keep a close eye on things. So far she’s doing great: her appetite has come back and she doesn’t seem to be bothered by the other crabs. Fortunately, her claw will grow back as she moults, so this will just be an awkward phase for her.