The naked sand darter (Ammocrypta beanii) is a member of the family Percidae. It is a small fish ranging in size from 40 to 50 mm long, the maximum being around 64 mm. Being a long thin darter, it is devoid of scales with the exception of a few rows above and below the lateral line and sometimes the caudal peduncle. Slightly transparent in life with a yellow color and iridescent operculum, the naked sand darter blends in with its habitat. It has darker bands in the dorsal, anal, and caudal fins with a whitish base and tip. Males of breeding size with have a dark spot at the front of the dorsal fin. Unlike similar darters, it does not have an opercular spine.