The rainbow darter is common in the upper Mississippi River basin. They are found in creeks and upper reaches of rivers in northeast Iowa in moderate abundance.

The rainbow darter is a fairly large and stout-bodied species approximately 2 1/2 inches in length. Its color is brownish-olive with 8 or 9 greenish-brown bars on sides, belly orange, cheeks bluish-brown, and the opercle is an irridescent golden green. The spinous dorsal fin is edged with blue and contains a row of reddish spots, sides with about a dozen bluish blotches, and fins of light orange. There are 12 dorsal fin rays, 7 anal rays, and scales along the lateral line are 45 or more. This species is the most brilliantly colored of all darters.

Rainbow darters inhabit creeks and small rivers of moderate gradient and riffles composed of coarse gravel and rubble. Under ideal habitat conditions of this type they may be locally the most abundant darter.

They feed on a variety of aquatic insect larvae and in some cases small snails and tiny crayfish.

Spawning takes place as the water temperature reaches 62 degrees F. Males have shifting, poorly defined territories and they attempt to intimidate intruding males. Females enter from pools downstream and lay eggs in gravel at the foot of riffles. The spawning act, with the male mounted on the back of the female, is repeated several times as she moves upstream. Several days may be required for a female to deposit as many as 800 eggs.

*Mayhew, J. (editor). 1987. Iowa Fish and Fishing. Iowa Department of Natural Resources, Des Moines, Iowa. 323 pp.