Mountain sucker

The mountain sucker (Pantosteus platyrhynchus) is a sucker found throughout western North America, on both sides of the Rocky Mountains, including the upper Missouri River, Columbia River, Sacramento River, and Colorado River. It is not limited to higher altitudes but is known from locations as high as 2,800 m (9,200 ft). It is a slender, streamlined fish typically under 20 cm (8 in) in length. It is generally olive green or brown above, with pale underparts, and breeding males have a lateral red-orange band and fins suffused with the same color. It is mainly herbivorous, feeding on algae and diatoms. Breeding takes place in late spring and early summer in gravelly riffles in small streams.

Formerly placed in the genus Catostomus, it is now placed in the genus Pantosteus. Recent phylogenetic studies suggest that it comprises three species: P. platyrhynchus sensu stricto found in the northern Great Basin, P. lahontan found in Nevada and northeastern California, and P. jordani found east of the Rocky Mountains.