Chihuahua Chub (Gila nigrescens) is a 20 cm long minnow that lives along 7.5 km of the Mimbres River in New Mexico and in the Guzmán and Laguna Bustillos basins in Chihuahua, Mexico. They can be found in softly flowing pools in small creeks and rivers, especially where there is cover from terrestrial vegetation or undercut banks. They are absent or rare when non-native fish are present.