The moapa dace is a rare cyprinid fish of southern Nevada, United States, found only in the upper parts of the Muddy River, and in the warm springs that give rise to the river. It is the only species of the monotypic genus Moapa.

Cyprinidae is a family of freshwater fish commonly called the carp or minnow family, including the carps, the true minnows, and their relatives the barbs and barbels, among others. Cyprinidae is the largest and most diverse fish family, and the largest vertebrate animal family overall, with about 3,000 species; only 1,270 of these remain extant, divided into about 200 valid genera. Cyprinids range from about 12 mm (0.5 in) in size to the 3 m (9.8 ft) giant barb. By genus and species count, the family makes up more than two-thirds of the ostariophysian order Cypriniformes. The family name is derived from the Greek word kyprînos.