C. DIABOLIS ORIGINALLY CAUGHT my interest because a weird little desert fish having a Vegas honeymoon at Mandalay Bay, watched over by government wildlife nerds, sounded like a scream. But then I went to Nevada and quit laughing. The Devils Hole pupfish matters.

It is, among other things, one of the founding endangered species, recognized and protected long before endangerment was an official status. In 1952, President Harry Truman proclaimed Devils Hole to be a detached part of Death Valley National Monument (now National Park), in order to preserve the hole's unique features, especially the fish.

In the late sixties, an agricultural developer sunk wells next to Devils Hole. The water level dropped alarmingly, to the point of baring parts of the spawning shelf. Thus began 15 years of court fights and public pissing matches—feds and enviros versus pro-development, anti-government Nevadans. A local county commissioner printed up KILL THE PUPFISH bumper stickers, and a newspaper in Elko called for some bold individual to clear up the problem by dropping poison into Devils Hole.

Just in time to save the pupfish, the feds got a court order to shut down the wells that were lowering the water level, which subsequently rebounded enough to cover the spawning shelf. Higher courts slapped down challenges all the way up to a landmark pro-federal, pro-pupfish ruling by the U.S. Supreme Court in 1976. The courts actually mandated a minimum water level in Devils Hole.

In 1980, another developer bought up land around Devils Hole. But once again the government intervened, and the company eventually sold its land to the Nature Conservancy, which in 1984 sold to Fish and Wildlife. The agency then established the Ash Meadows NWR, a miracle of wetness and green watered by 33 seeps and springs. Thanks to time and rehab efforts, Ash Meadows is slowly reverting to a facsimile of the paradise it was. And 27 species of plants and animals that are found only in the immediate area, a dozen of which are listed as endangered or threatened, have a home in perpetuity. For this triumph of conservation we can thank our unlikely hero, an inch-long fish.

One shudders to think what might happen without pupfish residing in Devils Hole. As one agency official says, on condition of anonymity, "Lose the fish and you lose it all." The "all" refers to a vast aquifer underneath the desert. Terry Fisk, a hydrologist for the National Park Service, says that, in the absence of pupfish, today's court-ordered water level would become negotiable. Lowering it could imperil Ash Meadows or jeopardize springs and endemic critters and plants down in Death Valley. So the Devils Hole pupfish is more than a relic—it's the future.

Fisk speaks the truest words I hear on the fate of the pupfish. "The poor little bastards don't have much going for them, do they?" he says. "But they're survivors. At least so far."