Iowa Darter

The Iowa darter has a very slim, small body. Its common length is around 5.5 cm and its maximum age is three years. It has a small mouth and snout with scaled opercles and cheeks, two dorsal fins, one which is a spinous-rayed fin and another soft-rayed fin. Its caudal fin is squarish and the pectoral fins and pelvic fins are located close to each other behind the gills. It has an anal fin with two (rarely one) spines and an incomplete lateral line. The male and female Iowa darters have different color patterns. During breeding, males are olivaceous dorsally with darker splotches across the top of their backs. Their sides are red with blue rectangular blotches and ventrally they are whitish with a dark wedge shape below the eyes. The bottom half of the spiny dorsal fin has blue spots between the spines and above the spots is a succession of three bands, orange on the bottom, clear in the middle, and then blue on the outside. Females are olive-brown dorsally with darker splotches across the top of their backs. Their sides are mottled and fade into a silver-white on their bellies. They also have a dark wedge shape below the eyes that is well developed.

Native distribution of the Iowa darter extends north to central Canada, east to New York, and south to central Illinois, and the species is particularly common in the western Great Lakes drainages and Iowa. Western populations are distributed patchily in Colorado, Wyoming, Montana, and Alberta. They are native in Colorado only in the South Platte River drainage, but recent research has also placed them in the Yampa River (Colorado) and the Green River.

The Iowa darter eats copepods, water fleas, and midge and mayfly larvae it finds in underwater vegetation. It has never been found in the stomach of any fish-eating animal because it is too quick to catch.

The genus name, Etheostoma, is from the Greek etheo meaning strain or filter and stoma meaning mouth. The species name, exile, also Greek, means slim or slender.

== References ==