Biologists have conducted two fish surveys along the Las Vegas Wash — the first from 2002 to 2003 and the second in 2019 after the completion of all 21 weirs. Surveys sampled a variety of habitats using hoop nets, minnow traps and seines. The 2019 survey incorporated gill nets to more efficiently target large-bodied fishes.

The initial survey provided a baseline as little information was available regarding the fish community in the area, identifying seven species, all non-native to the Colorado River Basin.

The 2019 survey showed changes to the fish community and habitat due to completion of stabilization and added large mouth bass, blue tilapia and short-fin molly to the Wash inventory.

Fish species at the Las Vegas Wash