Discoloration of Hermit Crab Claws

[Jessie J.]

Hi everyone. My purple pincher hermit crabs usually have pale eggshell white tips to their larger claws, but this morning all my crabs had brownish claw tips. They seem to be healthy and they act normal, but this strange coloration has popped up overnight. What's going on? Is it harmful? It has been chilly these last few nights, and their heater is not to the proper wattage (I'll have to get another one soon), is this contributing to or causing the problem? Thank you.

 

[Colin_T]

Theoretically they should not be able to change the colour of their shell except during moulting. Once the shell is made, it's dry, hard and presumed dead. It doesn't continue to grow or change colour. However, crustaceans can reabsorb calcium and other minerals from their shell before moulting so there might be some blood flow through the shell, or the crab can draw the minerals out of the shell wall and back into the body.

If all the crabs had white tips one day and brown the next, I would assume they found something brown to play in, maybe some food or something else. Alternatively they all shed their shell that night. It's unlikely but might have happened.

Monitor them and see how they go, it might be something new.

 

[Jessie J.]

Okay, thanks! They haven't had anything new in their terrarium for a couple weeks, so I'm really puzzled.