Used to have several fiddler crabs with some mollies in a 20g long, but they kept escaping, so had to rehome them. Crabs are cool though. Do you have any fish with yours, or would fish just be eaten? Is it a brackish, fresh, or salt water crab? How large is it?
Sorry for all the questions, but I'm always interested in animals I don't, or can't have.
150g long S Amer cichlid; 90g C Amer cichlid; 90g Malawi cichlid; 40g Tanganyika cichlid; 29g "Shellie" cichlid; 29g Pea Puffer. 6,500g koi/native catfish pond; several smaller ponds