Naked sand darter Naked sand darter The naked sand darter ("Ammocrypta beanii") is a freshwater fish of the family Percidae. It is found in the south-eastern United States. The naked sand darter 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
Yunnanilus macrogaster a short lateral line which has 6–10 pores and a line of pores on the head. The caudal peduncle is around 1.4 times as long as it is deep and its eyes have a diameter of slightly less than one fifth of the head length. It grows to a standard length of 63.2 mm. The body is yellowish with an irregular pattern of brown spots on its back and flanks with the dorsal surface of the head being darker and there is a dark patch on the operculum to the rear of the eye. The fins are hyaline and the