Colorado Lake Teems with Feral Goldfish

Parks and Wildlife thinks a goldfish owner dumped his pets into a local lake. Now a few years later, the fish swarm the water in thousands

Leonello Calvetti/Stocktrek Images/Corbis

Visitors to Teller Lake #5 in Boulder, Colo., say they can easily spot a creature that is so familiar and yet, in this context, so strange—a feral goldfish. Thousands of the common pet swarm below the lake’s surface—they're likely descendants of a lucky few whose owners thought swimming the lake would make for a better life than a measly glass bowl.

The Daily Camera reports:

Parks and Wildlife northeast region aquatic biologist Ben Swiggle believes the lake's goldfish population started from a handful that were dumped there by someone about three years ago, generating a teeming population now loosely estimated at 3,000 to 4,000.

"At least that's what we think happened," Churchill said. "We don't think someone fish-bombed the lake — although in the world we're living in now, I guess you wouldn't say anything is beyond the realm of possibility."

But the original fishes’ freedom came at the expense of the health of the rest of the lake – and it’s their progeny who will soon feel the consequences. “Nonnative species can be devastating to native populations by causing disease and creating competition unbalance,” Kristen Cannon, Boulder’s district wildlife manager, told ABC News. “We strongly encourage the public not to dump their unwanted pet fish in our waters. It is bad for our environment, as well as illegal.”

Boulder Parks and Wildlife plans to remove the fish, either by draining the lake or by putting an electric current in the water to stun the critters and then scoop their floating bodies off the top. (The agency already had success with the latter method when removing hundreds of koi from a different lake in 2012.)

The fish extermination won’t go wasted: Parks and Wildlife plans to feed them to raptors in a local rehabilitation facility. Goldfish are, after all, known as quite the tasty snack. 

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