the distinctive color of this fish is outstanding, having steel blue back and sides overlaid with silver shading and dark scale pockets that form a diamond design, with a prominent black blotch in the last few rays of the dorsal fin, sub-terminal mouth
very common in interior streams in north-central and northeast Iowa
insects, vegetable material, and some small fish
The spotfin shiner is very common in our interior streams in north-central and northeast Iowa, but it is found only in a few scattered locations in occasional abundance throughout western and southern Iowa streams. The spotfin shiner has a moderately slender body form and is slab-sided. The distinctive color of this fish is outstanding, having steel-blue back and sides overlaid with silver shading and dark scale pockets that form a diamond design. The anal fin of breeding males is often bright yellow, and the back is pigmented with olive green, shading to purple and blue. There is a prominent black blotch in the last few rays of the dorsal fin, which differs from the dusky fin of the red shiner. Dorsal, anal, and pelvic fins contain 8 rays, while the pectoral fins contain from 13 to 15 rays. A slightly sub-terminal mouth is oblique and has no barbel. Strongly hooked pharyngeal teeth on sturdy arches are arranged in a l, 4-4, 1 pattern. The complete lateral line contains 36 to 38 scales and is slightly de-curved.
The spotfin shiner prefers habitat that is shallow with swift water flowing over sand flats. Spawning sites are chosen over irregular surfaces so the eggs can be deposited into small crevices where they are safe through incubation. Spawning may occur over an extended period from May through August. Adults reach 3 inches in length and forage on insects, vegetable material and some small fishes. Spotfin shiners are displaced by red shiners when the habitat is altered by increased turbidity and siltation. This shiner makes an excellent aquarium fish and because of its brilliant colors is a good bait minnow.