If You Live in These States, Watch Out for Football-Sized Goldfish
This beloved pet may seem harmless, but it can become an invasive threat.
People have attempted to domesticate some ferocious animals, from tigers and lions to wolves and even alligators. In many states across the U.S., however, it's illegal to keep these animals as pets, forcing residents to stick to less dangerous options. But experts are now warning about one beloved pet that could become more of a threat than most people realize—goldfish. According to The Washington Post, waters across the country are being invaded by giant, football-sized goldfish.
When they can no longer take care of them, people sometimes decide to release tiny goldfish into a local lakes, ponds, and waterways. And while well-intentioned—they don't want to kill the creature—experts say this seemingly benign choice can result in massive goldfish. Przemek Bajer, PhD, owner of Carp Solutions and aquatic invasive species professor at the University of Minnesota, told The Washington Post that goldfish can live to be 25 years old, weigh as much as four pounds, and measure more than a foot long.
According to Bajer, goldfish live so long and grow so large because they can survive in severe conditions—even in winters where lakes have frozen over, because they can live months without oxygen. But their resilience can be harmful when they are placed in foreign bodies of water. And the problem has only gotten worse over the years, Bajer said. Read on to find out which states are now dealing with these enormous goldfish.
Groups of large goldfish were recently found in Keller Lake, the City of Burnsville, Minnesota, tweeted on July 9. "Please don't release your pet goldfish into ponds and lakes," the city's official Twitter account said. "They grow bigger than you think and contribute to poor water quality by mucking up the bottom sediments and uprooting plants."
"A few goldfish might seem to some like a harmless addition to the local water body—but they're not," the Minnesota Department of Natural Resources warned in a statement earlier this year. When feeding at the bottom of lakes, goldfish uproot plants and stir up sediment which not only damages the water quality, but also leads to algal blooms that can harm other species, per The Washington Post.
A Missouri man caught a nine-pound koi goldfish in Blue Springs Lake during the first weekend in July, according to a Missouri Department of Conservation Facebook post. The incident led the department to remind residents not to throw goldfish in the lake. "When pet owners dump ornamental fish like this, it can cause serious issues for native species. Instead of dumping aquarium fish, check with local pet stores who may take them back, or connect with aquarium clubs in your city," they warned.
In March, a fisher caught a 14.5-inch goldfish in Onondaga Lake, Syracuse.com reports. Neil Ringler, a SUNY biology professor who has been conducting net surveys on the lake with students since the '80s, told the news outlet that giant goldfish haven't presented any ecological problems in the lake so far—but they may not be existing and reproducing well, as no small goldfish have been caught during his years of research. "It seems they have access to the lake (in its tributaries), but are not thriving in it," he explained.
In Nov. 2020, a nine-pound goldfish was discovered during a fish population survey at Oak Grove Lake Park in Greenville County. Ty Houck, an official with Greenville County Parks, told NBC News that it was likely the only giant goldfish in the lake, as they did not encounter any others during the survey, so it is not yet being considered an invasive species to the lake.
In Virginia, a fisher was recently recognized for catching a goldfish that measured 16 inches in Hunting Creek. But the fish should have never been in the water. 'The introduction of goldfish to waterbodies is illegal in Virginia," the Virginia Department of Wildlife Resources reminded residents in a July 2 Facebook post. "Pet owners should never release their aquatic organisms into the wild as unforeseen impacts can occur including disease, competition, and predation."