Electric Blue Knuckle Crabs

[Mike62]

Is there a problem with introducing an electric blue knuckle crab into a tank with one or two already in there? I bought a new one this afternoon and put him in, and the others appear to be fighting with him. Is this normal? The moment I opened the bag to release him, both of them made a beeline for him.

[Benja]

They shouldn't be fighting unless there is a shortage of large shells in the tank.
They grow pretty quick... mine were always upgrading shells.