In the Mojave Desert lives an inch-long, slightly translucent fish that wouldn't look out of place in a home aquarium.
But the Devils Hole pupfish has much grander digs: a $4.5 million facility with a 100,000-gallon tank that mimics the fish's native environment, down to the rocky shelves where it spawns.
The facility is the latest chapter in a decades-long battle to save one of the world's rarest fish. Last fall, little more than 30 Devils Hole pupfish existed -- remnants of a species that has lived only in one spring for more than 10,000 years.
"It feels very precarious," said John Wullschleger, a National Park Service biologist on an interagency team focused on the fish. "You're just waiting for someone to go out there and not see any fish."
Pupfish occupy a deep hole connected to a vast aquifer, offering an extreme environment with 93-degree-Fahrenheit water and little oxygen. Devils Hole -- part of Death Valley National Park -- also reacts to earthquakes as far away as Mexico and Indonesia, with the water sloshing around its hole as if it were a bathtub and clearing out algae that the pupfish feed on.
With a life span of just one year, the fish have somehow survived for thousands of years with a population that probably rarely surpassed 700. But since 1997, pupfish numbers have suffered a sharp decline, to the bafflement of researchers.
Several attempts to set up a captive population have failed, either because the fish died or because they failed to reproduce. But a new facility offers new hope.
The Ash Meadows Fish Conservation Facility was built specifically for the Devils Holse pupfish. Funded through the sale of federal land, it features an in-ground concrete tank that scientists have painstakingly designed and nurtured to mimic Devils Hole.
Employees have gradually released 12 pupfish into its depths over the past few weeks. Last Friday, they released 17 more, in the hope that the fish would spawn.
If successful, scientists will be able to do what has eluded them for 40 years: conduct studies on one of nature's most mysterious fish.
"Devils Hole has always been an enigma because it's so unique in its location and in its fish," said Phil Pister, a California biologist known for his work on other species of pupfish.
"These are fully deserving of all the attention they're receiving."
The Devils Hole pupfish was one of the first species to gain endangered status in 1967, sparking a fight over water rights that ended up in the Supreme Court.
In a 1976 decision, the high court sided with the fish and the national park where it lived, upholding an injunction against groundwater pumping that had jeopardized the species' survival.
For years, the pupfish population seemed stable, if not numerous. In the fall, after a spate of spawning, fish numbered around 500. In the spring, the numbers would dwindle to around 250 or 300 due to die-offs in the winter.
But in 1997, that changed.
"It's pretty much been a steady decline for reasons we honestly don't know," said Darrick Weissenfluh, a biologist at the Fish and Wildlife Service who manages the Ash Meadows facility. "It could be everything from climate change to genetic issues."
Since then, the fish's numbers have dropped from an average of 275 to fewer than 100. Scientists have tried small, short-term measures to keep the population afloat, including some supplemental feeding.
But the fish has stubbornly remained vulnerable, one accident or reproductive failure away from extinction.
A 2004 incident highlighted that precariousness.
A university researcher had stored a plastic tub near Devils Hole, thinking it would secure about 20 traps made out of mason jars and funnels. But when a storm dropped several inches of rain, the tub was washed into the hole.
No one checked on the hole for several days, due to a flash flood in the national park that needed emergency attention. By the time an official make the trek, the traps had already killed about 80 pupfish, about half the population.
In many species, such events can spur a population upsurge after spawning, due to plentiful resources for the young. But the pupfish continued to decline.
For scientists, every move -- even feeding the fish or putting in artificial shelters -- seems filled with risk.
"You think, 'Could the actions we take to make things better be what pushes that population over the edge?' That's why it's been so difficult," Wullschleger said.
"There's always the potential that it could have some kind of unintended consequences."
No one knows the risks better than Pister.
On Aug. 18, 1969, Pister -- then a biologist with the California Department of Fish and Game -- carried the entire population of the Owens pupfish in two buckets.
"I carried these fish in two buckets across the desert in the dark to my pickup truck, hoping I would not trip," he said, remembering the "fear" of holding an entire species in his hands. "That makes you keenly aware of the fragility of this species."
Today, thanks to recovery efforts and Pister's work, the Owens pupfish numbers in the thousands.
But Pister called the work on the Devils Hole species unique. The fish's environment is so specific that biologists have had to create a customized, captive environment for it.
"We're plowing a lot of new ground here. We don't have many prior cases to build on," he said.
Federal officials have tried several times to set up a captive population of the Devils Hole pupfish, all without success. The fish either died because the tanks were not to their exact specifications, or failed to successfully spawn.
But a team of officials from NPS, FWS and the Nevada Department of Wildlife is hoping the Ash Meadows facility will reverse that luck, offering a location where a captive population can flourish and serve as a backup to prevent extinction.
Last fall, the count of pupfish in Devils Hole reached an all-time low of 35. Uncomfortable with taking out any adult fish in such a small population, scientists tried a new method: stealing eggs.
They placed tiles -- like those found on kitchen floors -- on the shelves of the spring and collected them after a few days. The result: 60 clear eggs, each 1 millimeter in size.
Of those, biologists fertilized a little more than half. Thirty-four hatched, and 29 survived -- a success rate Weissenfluh called "astounding for a first attempt at something that hasn't been done before."
Today, all of those fish swim in their customized 100,000-gallon tank, monitored by federal researchers who hope they will successfully spawn.
But the method was not attempted lightly.
"There were strong opinions on every side: people who wanted to take more, people who wanted to take less," Wullschleger said. "We were able to argue, and we were able to give and take. Everyone felt equally uncomfortable with the decision. And it bore fruit this time."
'What good are you?'
In April, biologists conducted their spring count in Devils Hole. The population had increased to 92, more than double that of the previous spring and fall. Officials hope it indicates even higher numbers for fall 2014, as spring is usually the population's low point.
The count also seems to demonstrate that biologists didn't jeopardize the Devils Hole population by taking out eggs -- a method that could perhaps be used for other species in the future, Weissenfluh said.
"I feel like we didn't give up," he said. "It was, 'Hey, here's some options. ... We're not down and out. Let's attempt something.'"
But some question the lengths to which the federal government has gone to save the Devils Hole pupfish. In an editorial last year, the Las Vegas Review-Journal argued that "the more the federal government spends to save the pupfish, the more they die off."
"Will someone dare suggest we pack up and leave Devils Hole alone, just to see how Mother Nature responds?" the paper says. "Can we at least turn the pupfish research lab into a lodge and spa, or put it to some other productive purpose, when the last fish passes away?"
Beyond a desire to not let the species go extinct, supporters of the effort point to the fish's role in preventing groundwater pumping by agricultural interests in the nearby area. Once it's gone, the prohibition could face more scrutiny and appeals, despite the existence of other endangered species in Ash Meadow.
But Pister, who calls himself an "environmental ethicist," says he has a stock answer for critics for the fish.
"I'd come back to anyone saying, 'What good are they?'" he said. "My response to that is, 'What good are you?'"