Colorado Fish Species: Flathead Chub

Courtesy of NDIS diversity listings, Colorado Parks and Wildlife

Habitat: The flathead chub is found in mainstems of often turbid streams and rivers, in areas of fast water with sand or gravel substrates. This species is tolerant of organic enrichment. Specimens collected from Fountain Creek downstream of the Fountain wastewater treatment plant effluent appeared to be in excellent condition. Water chemistry data collected from that location reveal extensive organic enrichment and high ammonia concentrations.
 
Description: A large, vigorous minnow; large subterminal mouth, moderate-sized barber located in the corners of the mouth, snout flattened with a broad, wedge-shaped head; pectoral fins large, sickle-shaped; eyes small, diameter of eye less than the length of snout; 44-50 moderate-sized scales in the lateral line; intestine short; lining of body cavity is silvery with few speckles. Adults are silver, although the back may be tan-brown in color. This is a large minnow which can attain a length of nine inches.
 
Range in Colorado: A widely distributed species, the flathead ranges frorn the Mackenzie River in Canada south through the plains states bordering the Rocky Mountains to New Mexico and Arkansas (Scott and Crossman 1973). Colorado populations are restricted to the Arkansas River Basin. Ellis (1914) reported the flathead as common in the Arkansas River mainstem up to Salida, where the river is a coldwater trout fishery. Recent collections have shown the species does not extend up the mainstem Arkansas River past a large diversion structure west of Florence. Other populations are found in larger tributaries to the Arkansas such as Fountain Creek and the Purgatoire River.
 
Status: State Special Concern