The humpback chub Gila cypha, is a federally protected fish that lived originally in fast waters of the Colorado River system in the United States. This species takes its name from the prominent hump between the head and dorsal fin, which is thought to direct the flow of water over the body and help maintain body position in the swift currents of the Colorado. The body is almost entirely scaleless, retaining only about 80 mid-lateral scales along the lateral line. The fish is very streamlined, with a thin caudal peduncle and a deeply forked tail. The back is a light olive gray, the sides silver, and the belly white. The dorsal fin usually has nine rays, and the anal fin 10 or more. Maximum recorded length is 38 cm.