Thousands of goldfish threatening a Colorado lake, again

A non-native — but instantly recognizable — species of carp is threatening a lake in Boulder County, Colorado, and state wildlife officials are blaming the situation on a careless pet owner. Several goldfish dumped into the lake years ago have reproduced with alarming success, and now thousands of the non-native fish are putting the aquatic ecosystem at risk, Reuters reported.

In March, Boulder County rangers reported that the lake’s goldfish population is somewhere between 3,000 and 4,000. Colorado biologists are determining the best way to get rid of the fish, which could require electrofishing or draining the lake.

It isn’t the first time this ubiquitous pet-cum-carnival prize has caused trouble in the state’s lakes. Colorado Parks and Wildlife spokeswoman Jennifer Churchill said that biologists used electrofishing to remove more than 2,200 goldfish from another lake a few years prior. While the highly adaptable goldfish can throw a lake ecosystem out of balance, a potential escape into downstream waterways could cause bigger problems for species including channel catfish and bluegill.