A remnant of the ice age, the Salish sucker is found only in a few small lakes and streams in and around Puget Sound in Washington State and in British Columbia's Fraser Valley. In British Columbia, Salish suckers are found in the headwaters of small streams. Adult suckers enjoy the slow waters of relatively deep pools with plenty of aquatic and bank-side vegetation. Young suckers are found in more shallow areas with abundant vegetation in the stream.

Considerably smaller than other suckers, Salish suckers reach approximately 25 centimetres in length. An inconspicuous fish, the sucker is dark green, mottled with black on top with dull grey-green flanks that bloom to a deep red during spawning. Its fleshy mouth is under the snout, well placed for bottom-feeding. Salish suckers live to about five years of age.