Riffle chub

The riffle chub (Algansea aphanea) is a species of freshwater fish in the family Cyprinidae that is endemic to the Armería, Ayutla and Tuxpan river basins in Jalisco and Colima of west-central Mexico. This threatened species is generally found in small rivers and streams in fast-flowing waters that are 18 - 22 C. It typically is 5 - 10 cm long.