The eastern sand darter (Ammocrypta pellucida) is a species of freshwater ray-finned fish, a darter from the subfamily Etheostomatinae, part of the family Percidae, which also contains the perches, ruffes and pikeperches. The eastern sand darter is a relatively small fish, most plentiful in the Mississippi and Ohio Rivers, as well as Lake Champlain and the Great Lakes. It prefers sandy-bottomed streams and sandy shoals in the lakes. The eastern sand darter feeds on larvae of black flies and other small insects in the water. They also feed on zooplankton in small portions since their small mouth size limits their gape ability. Its average body size is around 1.5-2 in long, and it breeds in the spring and summer in sandy-bottomed waters.