brownish-olive with a brassy luster above and silvery to white beneath, compressed laterally with a definite arch in back, subterminal mouth
small creeks throughout the northeast two-thirds of Iowa and along the entire length of the Mississippi River
algae and bottom ooze
The central stoneroller ranges throughout the northeast two-thirds of Iowa and along the entire length of the Mississippi River. It is occasional to common at most locations.
Body form of central stoneroller varies from slender to moderately stout, and they are slightly compressed laterally with a definite arch in the back. The horizontal mouth is sub-terminal and lacks a barbel. A cartilaginous and chisel-shaped lower jaw is a distinct characteristic of this genus. Slender arches support the slightly hooked pharyngeal teeth, which are arranged in a 4-4 pattern. The lateral line is complete, with scale counts from 49 to 55 in number, and the circumferential scale counts (around the body frontal of the dorsal fin) range from 39 to 55. Dorsal and pelvic fins ray count are 8, while the pectoral fins have 15 rays and the anal fins 7 rays. The long intestine is usually wrapped around the air bladder, and it is covered by a black peritoneum. Body color is brownish-olive with a brassy luster above and silvery to white beneath. Body sides are marked with scattered dark scales, giving the fish a mottled appearance. Spawning males develop a dark bar across the anal fin and have tubercles on their back, top of the head, and between the nostrils.
A small creek inhabitant, they are common in clear water streams and occasional to rare in larger, more turbid streams, reaching their greatest abundance in coolwater streams. Spawning activity peaks during April, when males excavate nests by moving gravel with their mouths or nudging it away with their snouts, giving rise to their common name. Stonerollers feed by scraping the algae and bottom ooze from submerged objects. Adults may reach 7 inches in length.