They have a pretty large hermit crab at the LFS and my son constantly bugs me to buy him. I have a large clown trigger, a smaller titan and a lion. Do you think a crab would have any chance of survival? I do have a couple of small snails that came in my live rock and they really don't mess with them. I think it would be a cool surprise for my son to come home and see the hermit in my tank. What do you think?