Last year, fishermen of Utah Lake, near Provo, Utah, began catching what looked like giant piranha. Come to find out the 11- to 30-inch fish were pacu, a vegetarian relative.

Unfortunately, these popular imported pet fish have been adopted, then dumped in the body of water nearest to the owners' homes. In some areas, these exotic aquatics have been able to establish populations and compete with aquatic species native to the area.

Don't think that southern Nevada has missed playing host to the whole feral pet scene.

Pet alligators are found in Lake Mead, having outgrown their previous owners' fancies or food bills. Aquarium fish that some family couldn't take with them when moving are taken to a city park pond, a community lake or the nearest public lands.

Even all the goldfish that are released in storm drains can end up surviving in an ecosystem in which they don't belong.

We assume that because our pets are animals, they are "at home" in the wild. Since most pets (especially if they were legally procured) have never even been near a wild environment, this simply isn't correct.

Even if one were to pick up his pet from a wild environment (which, by the way, is illegal) and then bring it back to that same environment, the wild-critter-turned-pet may not survive.

And pets from exotic places (like those pacu in Utah) can wreak havoc if the conditions are right for them to establish a population with which the native species have to compete for food, shelter, and water.

I recently got word that a few local pet fish were looking for new homes. I immediately asked myself what some people might naturally think: "Just take 'em down to that lake in Amargosa Valley." Now, before someone starts filling up a kiddie pool in the back of the truck and grabs the biggest fishing net they can find, let's think this through.

"That lake" in Amargosa Valley is actually Crystal Reservoir in the Ash Meadows National Wildlife Refuge, a body of water that is nearly all that remains of the days when this area was waist high in cotton and alfalfa.

Crystal Reservoir's new role is that of habitat -- habitat for some Ash Meadows Amargosa pupfish, migrating and wintering waterfowl, and, unfortunately, a slew of exotic aquatic species that the refuge staff is trying to remove.

Now these reservoirs, wetlands and spring pools are managed as natural habitat for the native species. Pets introduced into these environments bring more than just competition for food. Aquatic pet species, in particular, are apt to introduce some of their old environment into the new environment of the wild. That aquarium or pond they once called home was likely its own little ecosystem, with exotic plants and bacteria.

This ecosystem, when introduced to the wild, could introduce these foreign plants and bacteria that, without competition, may thrive. Result? Native fish, like the Ash Meadows Amargosa pupfish, could find their population wrecked by disease, parasites and predators.

The native species in the Ash Meadows area already have plenty to compete with, since largemouth bass, crayfish and bullfrogs were introduced. Other introduced fish compete with the pupfish for food and territory. As many of the native species found in the wildlife refuge area are found nowhere else, introducing more exotic competition for them could mean the loss of a species.

Of course, some of you may be asking, "So why should I care that we lose one little fish that I can't even catch to eat?"

Pupfish (there are three species found within the bounds of the refuge) and many of the other endemic (found nowhere else) species are relics. These are species whose genetics hail from eons back in time. They have survived scores of generations of climate change and human-induced environmental impact.

Pupfish, like many aquatic species found in our desert environments, have adapted very well to the climatological changes brought upon them. Scientists are now monitoring their adaptability to continued changes.

To use a common metaphor, these relic species are Amargosa Valley's "canaries in the mine shaft."

The Ash Meadows area is home to a higher concentration of endemic species than anywhere else in the United States. Only one other site even compares.

Not only is there value in simply appreciating the presence of such unique wildlife in the Ash Meadows area, but we may find that the fate of the native species of this area is more closely tied to our own than we have initially assumed.

For more information on where to take unwanted aquatic pets, please contact your local animal shelter.