Headwater Chub (Gila nigra) is a small (males: 50 cm, females: 10-18 cm) fish that occurs in the Gila River basin in Arizona and New Mexico. They prefer pools and runs near cover objects or deep water in the headwaters of rivers and creeks. They are highly omnivorous, feeding primarily on invertebrates and algae and are known to occasionally eat detritus, vegetation, and fish. Recent taxonomic work suggests that Headwater Chub in New Mexico may be the same species as two other limited-distribution fishes of the Lower Colorado River drainage, Gila Chub (Gila intermedia) and Roundtail Chub (Gila robusta).