A shell fight is when one hermit crab grabs a hold of another crabs shell and begins rocking it violently until the crab gives up the shell. Sometimes shell fights will result in death because the crab will not willingly leave its shell, so the aggressor rips it apart trying to remove it. Shells fights are a ugly part of hermit crab nature.
What causes shell fights?
Often just plain old jealousy. The aggressor wants the shell for itself. Other times, bringing a new crab home can start a fight. Its recommended that a new crab be isolated for anywhere from a week to 2 months depending on who you ask. After the quarantine period is over, you can bathe the new crab with the old crabs. This is to make them all ‘smell’ the same in hopes that the new comer won’t be attacked. The bath can be a shallow dish with dechlorinated water or even ocean water, placing the crabs in to wade around.
How can you prevent shell fights?
Offer plenty of empty shells for the crabs to choose from. Some similiar to what the crabs are currently living in and some new types of shells. More than one of each kind is a good idea as well. Hermit crabs change shells often, not just after molting.
How to break up a shell fight?
Most often when you approach the tank the crabs will pull back into their shells. If not, try picking them up and see if they release. Next step, try blowing on them gently, try misting them. If you still can not get them apart, try preparing a bath and place them in it. You most likely won’t have to take things this far, but its good to know in a pinch. 😉