Rainbow Darter

Characteristics

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

Distribution

Common in the upper Mississippi River basin; found in creeks and upper reaches of rivers in northeast Iowa in moderate abundance.

Foods

Aquatic insect larvae, small snails and tiny crayfish

State Record

State Records are not documented for non-game species.

Expert Tip

None

Details

Rainbow Darters live in creeks and small rivers of moderate gradient and riffles made of coarse gravel and rubble. Under ideal habitat conditions, they may be locally the most abundant darter.

Spawning takes place as the water temperature reaches 62 degrees. 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 needed for a female to deposit as many as 800 eggs.

Recent stream sampling information is available from Iowa DNR's biological monitoring and assessment program.