Montana Field Guide

Creek Chub - Semotilus atromaculatus

The creek chub is native to prairie streams in the extreme eastern part of Montana and is most common in the smaller Perennial Prairie Stream Ecological System. It differs from most minnows in that, similar to trout, the males dig a nest for the spawn and cover the fertilized eggs with stones to protect them. Creek chubs are also more piscivorous than most minnows, readily eating other small fish. In several areas of the U.S., creek chub are used as bait fish. They can attain a length of about 6 inches in Montana and 12 inches elsewhere.

The creek chub is silvery overall, often with purple iridescence; The back is olive and the underside white. Young have a prominent dark midside band extending from the tip of the snout to the tail fin; the band fades on older fish. The black spot at the front of the dorsal fin base is vague or absent in immature specimens. Breeding males usually have a reddish cast. A small, flap-like barbel is located in a groove of the upper lip just above each corner of the mouth, but is sometimes absent. Breeding males have a few pronounced projections on the head and smaller ones on the body and pectoral fins.

Montana Range

Creek chubs show a high preference for creek habitat. They are less frequent along the margins of rivers, lakes, and impoundments.

Creek chubs are very carnivorous. The diet includes insects, crayfish, snails, worms, and a considerable amount of fish. Also a small amount of vegetation is consumed.

Creek chubs are sexually mature at the end of the 2nd or 3rd growing season. Spawning occurs from late March through June. The male builds the nest and may spawn with several females.