Northern Prairie Wildlife Research Center
Description: This species is a small (l.l-2.5 inches, 38-64 mm) fish that is olive brown in color, with bronze reflections. It lacks the side bars present on the banded killifish. Breeding males have orange or red colored fins.
Habitat and Habits: The plains topminnow is found in clear, slow-moving streams with aquatic vegetation, quiet pools of small creeks and backwaters and overflow pools of larger streams. It occurs alone or in small groups near the water's surface. It deposits its eggs on aquatic plants or algae. Food habits of the plains topminnow are unknown.
Distribution: Two separate populations of the plains topminnow exist; one centered in Nebraska and ranging to adjacent areas in northeastern Colorado, eastern Wyoming and southern South Dakota; the other centered in southcentral Missouri, and ranging to southeastern Kansas and northeastem Oklahoma. In South Dakota, this species is documented from selected areas of the Vermillion, James, Cheyenne and Missouri River drainages. Although rare, it is sometimes locally abundant.
Conservation Measures: The plains topminnow may be an indicator of stream water quality. Populations should be monitored for changes in abundance or distribution.