Discarded, non-native fish find home in Clark County waterways

Lake Tahoe isn’t the only place in Nevada where you can find a 4-pound goldfish. Clark County waterways also harbor their share of aquarium escapees.

In the Las Vegas Wash, koi, mollies, goldfish and other popular pet store products are surviving and even thriving.

You know those little bottom feeders aquarium owners buy to help keep their tanks clean? They’re called plecostomus, a type of suckermouth catfish native to tropical South America, and some of the ones in the wash are a foot and a half long.

Then there is the red-bellied pacu, another South American fish that has found a home in the wash. It’s a harmless aquarium staple that happens to be related to — and look a lot like — the piranha.

Pacu don’t do so well in Lake Mead, where the water gets cold in winter, but suckermouth catfish, koi and goldfish all do fine.

Brandon Senger, Southern Region fisheries supervisor for the Nevada Department of Wildlife, said he never has seen a 4-pound goldfish at Lake Mead like the one that made headlines recently at Lake Tahoe, but he wouldn’t be surprised if they are in there.

After all, the goldfish is a type of carp. And as anyone who ever has stood on the dock at Lake Mead Marina with a bag of popcorn knows, carp do just fine in the nation’s largest reservoir.

FROM PETS TO PESTS

Seth Shanahan is a senior biologist for the Southern Nevada Water Authority who works extensively with the Las Vegas Wash Coordination Committee.

He and his fellow researchers haven’t even identified some of the exotic fish swimming around in the wash, he said. “That’s because we haven’t gone to Walmart and looked at all the fish tanks to compare.”

There is little doubt about where they came from.

Shanahan said the exotic fish often can be seen near roads and other access points along the wash. On occasion, researchers have found broken glass and other evidence of aquarium dumping along the shore.

“The blue rock is the telltale sign,” he said.

So far, the one-time pets don’t seem to be causing any problems in the wash. Then again, there isn’t really a natural order for them to upset in a man-made channel filled with the valley’s treated wastewater and storm runoff.

The same cannot be said for other spots in Southern Nevada, including Rogers Spring near the northern tip of Lake Mead and the Warm Springs area at the headwaters of the Muddy River. In both places, aquarium fish now live side-by-side with fragile native species that don’t really need any extra competition.

The aquatic interlopers are easy enough to see. At the Moapa Valley National Wildlife Refuge, about 60 miles northeast of Las Vegas, there is a display window where you can watch the endangered Moapa dace swim in a spring-fed stream.

You also can see the ubiquitous molly, an adaptable little tropical fish that is using the aquarium business to expand its range in the natural world.

Luckily, mollies don’t eat dace, but they do multiply and feed on some of the same things as their rare desert neighbors do.

“They don’t belong there, put it that way,” said Dan Balduini, spokesman for the U.S. Fish & Wildlife Service in Nevada. “They’re just non-native — way non-native.”

Senger said the warm water of Rogers Spring is loaded with the descendants of aquarium refugees native to tropical Africa and South America.

That’s bad news for the relict leopard frog, which was thought to be extinct until they were found again in Southern Nevada during the early 1990s. Tadpoles are easy pickings for mollies and other exotic fish, Senger said.

A HOME FOR HOMELESS FISH

For years, the Fish & Wildlife Service and the National Oceanic and Atmospheric Administration have teamed with pet and nursery industry representatives on a public education and outreach program aimed at keeping aquarium fish in aquariums.

Some people appear to be getting the message.

Lisa Riggs runs Trop Aquarium, an aquatic pet shop her parents opened in 1978.

Asked if people ever bring her their unwanted fish, she said, “Every day, by the bucket full.”

Riggs said the biggest reason pet fish wind up back at pet shops — or dumped into the wash or lake — is because they outgrow their tanks, something that can easily happen with suckermouth catfish, pacus and oscars.

“We take in all homeless fish,” she said. “Sometimes we even give (store) credit for them.”

People also drop off unwanted turtles and more exotic fare, she said. One time, someone left a 10-inch caiman — first cousin of the alligator — in a paper bag in the middle of the store.

“Never found out who did it. We called fish and game, and they came and got it,” Riggs said. “It was the strangest thing.”

Giving pet owners an alternative to emptying their tanks and ponds into the nearest body of water is important, because some species are almost impossible to kill once they get loose.

Senger said the molly, for example, is “tough as nails” and equipped to survive under a wide array of conditions.

Also, he said: “They’re really cheap in pet stores, and they reproduce like mad.”

Contact reporter Henry Brean at hbrean@reviewjournal.com or 702-383-0350.