Montana Field Guide

Iowa Darter - Etheostoma exile

There are about 100 species of small perches called darters. In Montana we have only one representative, the Iowa darter. It is a native fish found in small streams and reservoirs in the plains region of our eastern drainage. During the spawning season, this species becomes one of Montana's most highly colored fish. The major food items of Iowa darters are insects and crustaceans. Its maximum size is a little less than 3 inches. It is not abundant enough to be an important prey species in Montana.

Iowa darters are greenish or brownish with about eight saddle bands across the back and about nine to twelve dark blotches on the side. In breeding males these blotches become bluish-green with rust-red between them. The underside becomes orange and the first dorsal fin has a reddish band between a blue outer edge. The body is slender, the eye large, and the lateral line incomplete.

Montana Range

Iowa darters prefer clear slow-flowing streams with solid bottoms. They are also in lakes and reservoirs. They seem to prefer abundant submerged aquatic vegetation.

Food consists mostly of small crustaceans and aquatic insect larvae.

Iowa darters spawn May through July in groups. Eggs are deposited on or among stones in shallow water. Incubation is for 18 to 26 days. No parental care is given the young. Fish become brightly collored when spawning.