The Woundfin (Plagopterus argentissimus) once ranged from southwest Utah to southern Arizona in the Colorado and Gila River basins, but now only occur in 12 percent of its historical range, and is classified as critically endangered. It prefers quiet water adjacent to riffles of swift, warm, turbid small to medium rivers, but spawns in swifter flowing water over gravel. Populations have been affected by habitat loss, fragmentation, and degradation caused by dams and water diversions. Woundfin populations have also shown declines in areas where the non-native Red Shiner has proliferated due to changes in water flow patterns caused by dams and diversions. The Red Shiner is both a predator of and a competitor with Woundfin, but the Red [...]