“Want to see one of the rarest trouts in the world?” asks Ed Stege, who has just netted a pair of greenback cutthroats from one of the trough-shaped tanks at the Leadville National Fish Hatchery. Greenbacks are Colorado’s state fish, but with only about 750 remaining in the wild, few Coloradans have ever seen one, including me. That is, until I peer into the five-gallon bucket, where Stege has deposited his precious specimens—just two of the 550 members of this endangered species he cares for every day.

Speckles cover the young fishes’ army green spines, which fade into white bellies that can turn reddish as they age. Stege shows off their orange fins, which are robust, not ragged like you might see at less-capable hatcheries. As the manager of this brood, Stege is the latest in a long line of fish culturists who have manned the hatchery since 1889. In those days, these tanks raised rainbow and other non-native trout that were then stocked throughout Colorado to augment existing populations. “My forebears were the Johnny Appleseeds of the fish world,” says Stege with clear pride. That may be true—and I suspect those early fish hatchers fancied themselves pioneers in fish farming and propagation—but their successes had serious long-term consequences. For much of the past 124 years, the fish Stege’s predecessors stocked in Colorado’s lakes and streams helped wipe out two of Colorado’s six native trout species.

Today, Leadville’s National Fish Hatchery has redirected its efforts to rehabilitating the natives that remain—particularly the greenback cutthroat trout. Leadville’s charges, which the hatchery has been raising for three years, are now 10-inch-long adults whose progeny will be ready for release into the wild this summer.

With friends like us, you sure don’t need enemies, do ya pals? I think as I peer down at the two bucket-bound trout awaiting our next move. Stege reaches in and lifts one out of the pail so I can get a better look. An avid angler, I get a thrill every time I come nose-to-nose with a trout, but this time, I’m aware that I’m gazing at a relic of what a wilder, freer Colorado offered before civilization builders moved in and re-engineered the rivers (along with everything else). This fish is a living museum piece, the dodo before its demise. But as I look at this beautiful creature, I consider the larger implications of rehabilitating and reintroducing its species. I’d love to see his kind return from exile to swim once more in the high mountain streams that feed the South Platte River, his native home. Instead, I ask him a question: “Little greenback, are you worth all this trouble?”

It’s easy to criticize human beings’ penchant for meddling with nature’s designs. After all, even our best-intentioned intrusions often end in regret (witness the kudzu plant’s stranglehold on the South or the imported European starlings that rain poop on New York City). But we do occasionally get lucky, as we did when an early Colorado entrepreneur named J.C. Jones thought it’d be nice to have some trout swimming in the stream near his homestead. Living near the base of Pikes Peak in 1873, Jones introduced a few greenbacks to the otherwise fishless Bear Creek flowing through his property.

Although greenback cutthroats once flourished in the headwaters of the South Platte River, those fish lost their battles with overharvesting, mining, timbering, and competition from non-native trout species—and were declared extinct in 1937. Amazingly, they resurfaced in the 1950s, when greenbacks (or what biologists thought were greenbacks) turned up in streams across the Front Range, including Bear Creek. After greenbacks were added to the endangered species list in 1973, a decades-long rehabilitation effort ensued as Colorado Fish and Wildlife (and other organizations) spawned members of those scattered populations and introduced them as “stocker” fish to 58 high-mountain streams and lakes. Officials excluded Bear Creek fish from the brood stock, thinking that those fish—which looked a smidge different from the rest of the “greenbacks”—might be a corrupted population.

But in 2007, research into the cutthroats’ DNA revealed that those stockers weren’t actually greenbacks, but Colorado River cutthroat (which are native to the Yampa River and White River basins). That study also confirmed that the only place where true greenbacks survived wasn’t some remote alpine stream, but one that babbles just 20 minutes from the bustling city of Colorado Springs. Bear Creek, which likely never supported a trout population before J.C. Jones created his backyard aquarium, contains the planet’s sole population of genetically pure greenback cutthroats.

In an attempt to rectify their species mix-up, Colorado Parks and Wildlife removed 65 of Bear Creek’s approximately 750 genuine greenbacks to serve as brood stock at state and federal hatcheries. “The goal is to move these fish to more places in Colorado,” explains senior aquatic biologist Doug Krieger, leader of Parks and Wildlife’s Greenback Cutthroat Recovery Team. “Having the entire [wild] population in just one place does make us nervous,” he says, explaining that floods, wildfires, or other natural disasters affecting Bear Creek could wipe out all but the hatchery specimens. To mitigate that risk, volunteers from diverse groups—Colorado Motorcycle Trail Riders Association, Trout Unlimited, Rocky Mountain Field Institute, and Medicine Wheel Trail Advocates—have helped re-route trails away from Bear Creek’s banks to reduce erosion and preserve the deep, sediment-free pools trout need to survive drought and extreme cold.

Meanwhile, Colorado Parks and Wildlife has been preparing high-mountain lakes to receive the first true greenback cutthroat stockers. With captive populations now numbering 3,500 members (most adults are at Leadville, while state hatcheries care for a few thousand small fry), Krieger expects to release some of the biggest specimens this summer into lakes near Guanella and Cameron passes. Bringing these fish back “enriches the environment we live in and the natural world people enjoy,” says Krieger. “In Colorado, we probably appreciate that more than in a lot of places.”

As naturally blessed as Colorado is today, it’s a bit sad to think that it once had even purer streams, cleaner summits, and more abundant wildlife. Imagining returning parts of our state to those original, pristine beginnings is, of course, an enticing prospect. But here’s the catch: Reversing development corrosion doesn’t come cheap, in terms of effort, collateral damage, or dollars.

Federal and state agencies spent about $396,000 in fiscal year 2010–2011 (the most recent estimate) on greenback cutthroat rehabilitation efforts, which require significant manipulation to existing species and waters. Using gillnets or a toxicant called rotenone, land managers must remove non-native fish from the repopulation zones to prevent hybridization and eliminate competition with species that nearly decimated the native trout in the first place. If lakes and streams don’t contain natural barriers (like the small waterfall on Bear Creek that isolated its greenbacks from other fish downstream), officials build them to help the reintroduced natives become self-sustaining populations.

Strengthening the greenbacks’ presence in the landscape would permit anglers to cast for trout that have long been off-limits to them, but better fishing isn’t what’s driving rehabilitation efforts. In fact, most anglers care little for native trout, says Nick Hoover of the Greenbacks, an offshoot of Colorado Trout Unlimited that conducts outreach and fund-raising on behalf of the state’s most beleaguered fish. Because most enthusiasts cast for monsters, not minnows, explains Hoover, “It can be hard to convince the common angler to protect a species that typically only grows to six or eight inches.”

Not only are greenbacks small, they may also be insignificant—at least from an ecological standpoint. According to University of Colorado Boulder professor Andrew Martin, who contributed to the 2007 and 2012 cutthroat genetic studies, “The greenback has no objective value based on how it performs in the environment.” Any cutthroat trout would serve the same function in the food web.

The greenback’s greater value, Martin maintains, is its cultural richness. “It tells us a lot about evolutionary history and the development of Front Range watersheds,” he says. Just as an original Van Gogh has greater worth than any reproduction, the greenback is more valuable because of its uniqueness than browns or rainbows. “You can plug in a substitute that will function ecologically,” says Martin, “but it wouldn’t be a greenback that evolved in that range for literally millions of years.”

And so the redesign of Colorado waterways continues, only this time it’s intended to remedy past mistakes. The irony isn’t lost on Anders Halverson. Author of An Entirely Synthetic Fish: How Rainbow Trout Beguiled America and Overran the World, Halverson advises caution. “They were sure they were doing the right thing by spreading those non-native species, and I hear that now from people wanting to reintroduce greenbacks,” he says. “There will be unpredictable consequences of any attempt we make to engineer or re-engineer our ecosystems.”

But Halverson also holds this truth to be self-evident: We should preserve as much biodiversity as we can. “Two out of every three fish swimming in the state of Colorado are non-natives,” he says. “It’s sad and impoverished. It’s like eating at McDonald’s everywhere you go for every meal. To me, that’s just tragic.”

Further, all life—from humble trout to inquisitive journalist—is deserving of respect, Stege says. “What good are they?” is a question he heard a lot throughout his previous post at Saratoga National Fish Hatchery, where he resuscitated the Wyoming toad (then the most endangered amphibian in North America). Hearing me utter it again in reference to the greenback piques his annoyance. As Stege carefully returns his scaly friends to their tank, he looks at me and answers a question with a question: “What good are you?” he asks. “What would the world lose if you weren’t here? You have no idea down the road what each unique species may contribute.”