I was also thinking red claw, but I guess not. Just keep a tight fitting lid on your tank, crabs are escape artists. I can't even count how many times my red claws would come out of my tank and scuttle around the floor, They'll use anything they can find to scale the tank i.e filter intakes, power cords, air line hosing you name it. When you do have everything working for you though, they make interesting pets 
