Nipping at the heels of potential mates, the stout, ray-finned pupfish gained its namesake from its striking resemblance to frolicking young puppies. Cousins to the well-known guppy, pupfish are not only playful but are also remarkably tolerant of extreme environmental conditions. The desert pupfish is no exception. Dwelling in pools, marshes, streams, and springs of southern Arizona and California, the desert pupfish has an extraordinary ability to survive, enduring water temperatures that can exceed 110 degrees and tolerating water more than twice as salty as the ocean.

As hardy as it is, the desert pupfish must struggle to stay alive against the impacts of livestock grazing, water diversions, and competition from nonnative species. The Center first championed the fish in 1996 when we filed a lawsuit resulting in the Bureau of Land Management cutting back the number of cows on the Gila River, and perhaps more importantly, forcing the agency to acknowledge livestock's deleterious effects on endangered species like the pupfish.

In the years since, we've worked to protect the fragile Colorado River delta, safeguard the Salton Sea, and restore full flows to Arizona's Fossil Creek — all waterways that are indispensable to pupfish. But threats to the desert pupfish persist, and we're now in court challenging the 45-million-acre Southwest National Interest Electric Transmission Corridor, which as planned would run powerlines through an area of prime pupfish habitat.