The average length of the adult Chiselmouth is 6-7 inches (15-18 cm). The head is blunt and they have a relatively large eye. The lower lip is covered with a hard cartilaginous sheath with an almost straight cutting edge rather like a chisel giving it the ability to scrape algae from rocks. Their overall colouration is a rather drab dark brown with lighter sides covered in many small black dots.

Columbia Basin: Lake Windermere

British Columbia: Known only from a few scattered locations in the Columbia and Fraser River systems: Okanagan River; South Okanagan Lake; Missezula Lake, Wolfe Lake and Creek, the Kettle River; West Road River; and Mara Lake.

Global: Outside of B.C. known only from the Malheur Lake drainage in central Oregon.

Seems to prefer faster water of warm streams, but is also found in backwaters of larger rivers, small kettle lakes and large lakes. Although it has not been observed, spawning occurs in streams

Biology and critical habitat requirements are still largely unknown. Although its range is confined and its distribution spotty, it is found in numerous localities and a variety of water body types, and has no obvious threats (Cannings and Ptolemy, 1998).

Young chiselmouth feed mainly on insects, while adults feed largely on diatoms that they scrape from rocks or other substrate with their lower chisel-like jaw. Spawning usually occurs in late June to early July when water warms up. During spawning, eggs have been found on the open bottom and buried among boulders (Scott and Crossman, 1973). Maturity occurs at age 3 or 4 years and may live to 6 years (Cannings and Ptolemy, 1998).