THE SUCCESS WITH OTHER PUPFISH shows how well aquarium propagation can work. All sorts of fish looking at the Big E have turned their luck around in just such a manner. So why not the Devils Hole pupfish? On the way out of Vegas, at the wheel of a dusty USFWS Jeep bound for Devils Hole, Cynthia tells me. "Guess what," she says. "We don't know how to reproduce them in aquaria." Top fish people have tried and failed despite lots of promising fish sex; only one hatchling has reached adulthood.

I am fortunate in the federal ecocrat assigned me. Cynthia does her best to communicate in approved resource-manager fashion, but she repeatedly fails. She likes to tease and make gotcha jokes, with a cowgirl bounce and sass that hark to her native New Mexico. I ask her to lay odds on the pupfish's survival. She asks sarcastically for clarification—survival in Devils Hole or elsewhere, with Devils Hole–like fish bred back from the hybrids? Then, seriously, she says, "I still think we will be successful. Otherwise, I wouldn't spend so much time on it." The odds are, in her opinion, better than 50 percent.

In light of recent calamities, I'm guessing she means 50.0001 percent. In the late nineties, a decline was noted in the number of adult Devils Hole pupfish, counted in spring and fall by divers. Nobody panicked because, among other things, the fish were coming off all-time highs of nearly 600 in the previous few years. The presence of seemingly healthy pupfish populations in three operating refuges also gave comfort.

But in 2002, with counts in Devils Hole down to about a third of the mid-nineties' highs, Fish and Wildlife, the National Park Service, and Nevada's Department of Wildlife formed the Devils Hole Pupfish Recovery Team. Experts looked long and hard into the hole and saw a mystery that's still unsolved. None of the usual suspects that do in native fish—nonnative invaders, habitat degradation, pollution—has been found in Devils Hole. The babies were simply not growing up.

To learn more, the recovery team approved a field study, which led to the worst thing that ever happened in Devils Hole: Pupfish 9/11. Really. On September 11, 2004, a storm caused runoff that washed a box of the researchers' fish traps into Devils Hole. The traps sat unnoticed for four days.

Eighty adult fish perished in those traps, a third of all wild Devils Hole pupfish at the time.

By then, things had already gone south in two out of the three refugia—a fancy word for the roofed-over concrete pools that are the only places outside Devils Hole where the species has managed to multiply. A pump failure zotzed all the fish in the refuge at School Springs, in neighboring Ash Meadows National Wildlife Refuge. Around then, it became apparent that the fish in the nearby Point of Rocks refuge weren't actually C. diabolis. Nobody knows how, but one or more wild Ash Meadows pupfish, C. nevadensis mionectes, got in and corrupted the population, creating the horndog hybrids currently making babies at Shark Reef. The last blow came this year with the shutdown of refuge number three, near Hoover Dam. It got slammed by a hyperinvasive nonnative snail that eats pupfish food. All three refuges remain fishless.