I have several blue legged hermit crabs and often bought them as little guys and I've noticed I have one that has grown up into a red legged hermit crab! Right now its about the same size as my bigger blue legged ones but i don't want to leave him in there if he's gonna kill all the others. At what size do they start to become a bother? I think he'll get a little nano tank, but I don't know how quickly to rush this project.