Blackstripe topminnow

Characteristics

back and uppersides are olive with white below, prominent dark stripe on the sides, nearly straight edged in females and with crossbars in males, top of head and nape distincly flattened

Distribution

streams in eastern Iowa and pools 16 - 20 of the Mississippi River

Foods

aquatic and terrestrial insects

State Record

3 inches

Expert Tip

Details

The blackstripe topminnow is found in streams in eastern Iowa and has been collected in pools 16 through 20 in the Mississippi River. It seems to prefer small streams where the current is moderate or lacking.

A slender-bodied, almost cylindrical topminnow, the blackstripe topminnow has the top of its head and nape distinctly flattened. The snout is pointed, and the mouth is small, oblique and opens dorsally. It has a projecting lower jaw with very small teeth in bands on both jaws. The dorsal fin is far posterior on the back and is inserted into the body behind the origin of the anal fin and contains 8 to l0 rays. The anal fin has l2 rays, pelvic fin 6 rays, and the caudal fin is rounded. The lateral line is incomplete with 3l to 36 large, cycloid scales in a lateral series. Its back and upper sides are olive and white below. The sides have a prominent dark stripe, nearly straight edged in females and with crossbars in males. Adults average l l/2 to 2 l/2 inches in length with a maximum of just over 3 inches. Males grow larger than females.

Blackstripe topminnows usually travel in pairs consisting of a male and a female during the late spring and summer spawning season. The pair defends the spawning territory against others of their own species. Eggs are deposited singly on aquatic vegetation as the pair lie side by side. Up to 20 to 30 eggs can be deposited over a short time period, which is usually repeated after several days. Aquatic and terrestrial insects provide most of the adult diet.

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