Males have a large claw that they wave back and forth like a fiddler.
Fiddler crabs are so named because the males have one large claw that they carry in front of their bodies and move back and forth at times like a fiddler. The large claw is also used to establish a territory and attract a mate. Found near salt marshes, they burrow their bodies in the mud. They feed on organic material found in the mud then deposit the leftovers by bringing up round, pea sized balls of mud to the entrance of their burrow and snapping the balls out with their legs. Human encroachment upon the wetland habitats of the crab has made the future of fiddler crabs uncertain. Fiddler crabs are usually found at the Aquarium in tank number 26.