Wildlife officials claim that the only way to combat the problem may be to drain Boulder’s Teller Lake. Although goldfish may seem to be the most innocuous of freshwater fish, they have devastated the lake’s fragile ecosystem, writes Melissa Chan for New York Daily News.

Officials Bemoan Goldfish Invasion Of Colorado Lake

Officials condemn goldfish dumping

Colorado Parks and Wildlife officials claim that a handful of unwanted goldfish were given a new home in the lake around two years ago, before reproducing rapidly into a school of 4,000.

“Goldfish are not a native species and are very harmful to the local aquatic ecosystem,” said Kristin Cannon, Boulder’s district wildlife manager. Despite the fact that goldfish are given away at the circus and are not generally thought to be the most exciting fish, it seems they have a dangerous side after all.

“We strongly encourage the public not to dump their unwanted pet fish in our waters,” Cannon added. “It is bad for our environment, as well as illegal.”

Two possible solutions: electrofishing or draining the lake

In November 2012, over 2,000 invasive koi goldfish were removed from another Boulder lake using a technique known as “electrofishing,” which involves paralyzing the fish using electric current before collecting them in nets and removing them from the lake.

Officials are pondering whether or not to use the same technique at Teller Lake, while another possible option would be to drain the lake entirely.

“Most people don’t realize the far-reaching effects of introducing exotic species to the environment,” said Ken Kehmeier, Colorado Parks and Wildlife senior aquatic biologist. “Nonnative species can be devastating to native populations by causing disease outbreaks and creating competition unbalance,” he said. “It’s an issue that anyone concerned with our environment should know about.”

It just goes to show that even the most innocent of animals can cause major environmental problems if they are introduced to habitats in which they are nonnative, disrupting the delicate balance of ecosystems and causing the need for drastic action such as the draining of an entire lake. I wager that the former-goldfish owner had no idea that the 5 unwanted swimmers would survive in the lake, let alone swell into a school of 4,000.