The Owens pupfish once inhabited the network of rivers, streams and springs that meander through California’s Owens Valley at the base of the Eastern Sierra. They were found from just north of Bishop south to Lone Pine. The small but mighty fish’s habitat began to shrink in the early 1900s as water in the Owens Valley was diverted for other uses. Coupled with competition from, and predation by, nonnative introduced amphibians and fish like large mouth bass, Owens pupfish populations declined and the U.S. Fish and Wildlife Service listed them as an endangered species in 1967. Owens pupfish are small, rarely larger than two and a half inches long. The females are a dusky, olive-green color and the males are bright blue, particularly during their spring and summer spawning season. The pupfish continue to be threatened by habitat loss and nonnative fish and amphibians as well as climate change.