Flannelmouth sucker
(Catostomus latipinnis)

Catostomus latipinnis (flannelmouth sucker) is a North American fish identified by its enlarged lower lips. It belongs to the genus Catostomus, commonly known as suckers. Historically, the flannelmouth sucker ranged in the Colorado River Basin, including parts of Wyoming, Utah, Colorado, New Mexico, Nevada, California, and Arizona; however, this species has been entirely extirpated from the Gila River Basin in Arizona.

The flannelmouth suckers body is long, starting with a thick anterior that moves down to a thin posterior; respectively, this causes the head to be relatively short and thick. The lower lips are noticeably bulky, with thick and fleshy lobes. In addition, the flannelmouth sucker has large fins, but relatively small scales.

Flannelmouth suckers are classified as benthic fish, spending most of their time near the river floor where they forage for food.  Young fish are usually silvery-colored all over, but adults have a typical light gray or tan coloration (often with a lighter underside). Strangely, no bright colors have been found in populations of this species in Arizona, but are found in those from the Colorado basin.

Adult fish can also grow to a length of 26 inches and weigh about 8 pounds. It is one of the largest of all suckers.

The flannelmouth sucker can be found in parts of Wyoming, Utah, Colorado, New Mexico, Nevada, California, and Arizona. In Arizona, this species is found in the Colorado River and its larger tributaries.

In the mid 1970s, the Arizona Game and Fish Department introduced the fish below the Davis Dam, and the population still persists today.

It is extinct in California although strays from the reintroduced Nevada population are occasionally caught in the Californian Colorado River.

While flannelmouth suckers are restricted to larger rivers, its larvae tend to live in shallow areas. Larvae also like deeper water when they are not feeding. In addition, adult suckers prefer great amounts of cover and shade during the daytime.