SHARK REEF'S THREE PUPFISH, the pair I see and a male bystander, are tanked in a small room off an immense nonpublic holding area used mainly for newly arrived creatures. To get here, I walked through Mandalay Bay's casino and stopped to drink coffee at the foot of a huge, headless statue of Vladimir Lenin—complete with realistic pigeon shit—that proclaims the Russian-ness of Mandalay Bay's Red Square restaurant.

Authenticity is the fantasy in the new Las Vegas; witness Shark Reef. Though Las Vegas itself may be an affront to conservation, and the mind rebels against the idea of a resort/casino/world-class public aquarium complex with official accreditation and peer respect and scientific props, Shark Reef is pretty much that. So far, management maintains a dignified silence—not a peep from PR—about its new, potentially species-saving emergency effort.

"We've laid extremely low, because our attachment to this has always been on the conservation side," says Jewell, who adds, "We have no shortage of PR—this is Las Vegas, for God's sake." Jewell says the pupfish work is strictly pro bono. He declines to put a dollar value on the hours he and his staffers devote to the pupfish, because he hasn't kept track. "Support from management is so strong, I've never even been queried on that," he says.

Jewell says he started talking with pupfish people a few years back, with the idea of breeding Devils Hole pupfish both to help boost the population and to spotlight a Nevada fish in Shark Reef's educational programs. A public exhibit was in the cards, too, but is now indefinitely on hold, because the situation is so dire. Jewell's preparations to host C. diabolis began about a year and a half ago, when he brought in closely related Saratoga Springs pupfish. They're thriving, with some on display in Shark Reef's classroom for visiting schoolkids. Jewell has also had success with recently arrived accidental hybrids crossing the Devils Hole species and one of its closest kin, the Ash Meadows pupfish. (There are close to 40 species of pupfish in all.) Jack pulls an omigod face to express the hybrids' hell-bent fecundity. After only a couple of months, Shark Reef–hatched young are already trying to mate.