Habitat
Habitat includes perennial creeks and small to medium rivers, canals, lakes, ponds, and ephemeral habitats with high turbidity and few competing species; silty, sandy, and rocky pools and runs, sometimes riffles (Sublette et al. 1990, Page and Burr 2011). This species often is the most abundant minnow in a wide variety of low gradient habitats, especially backwaters, creek mouths, and medium-sized streams with sand/silt bottoms. It is uncommon or absent in clear high-gradient streams. It selects water with negligible (or intermittent) flow deeper than 20 cm, and it avoids temperature extremes in summer and winter, but does well in harsh and variable environments when other species disappear (Mayden 1989). Spawning occurs in quiet waters of lakes or streams, often over sunfish nests, clean gravel or sand of riffles, submerged roots or logs, or aquatic plants, or on rocky shorelines in crevices. Eggs sink and adhere to bottom (gravel, sand, or mud). Male defends spawning territory.
Reproduction
Spawns in spring and summer; probably June-August in Wisconsin, May-August in Illinois, May-October with June-July peak in Kansas and Missouri, April-September in Texas and Oklahoma. One-year-olds spawn in late summer after two-year-olds. Eggs hatch in ca. 105 hours at 24.5 C. May produce several clutches each year. Sexually mature in 1-2 yr.; most breed in second summer, very few in first summer (Mayden 1989). Reproduction by young-of-the-year likely facilitates attainment of numerical dominance in many sites where this species has become established (Marsh-Matthews et al. 2002).