Researchers in California and Nevada said the gigantic goldfish found in Lake Tahoe have also been spotted in waters around the U.S. and as far away as the United Kingdom and France.
According to KCRA-TV, a team from the University of Nevada-Reno (UNR) and University of California-Davis (UCD) have been spotting the mammoth fishes, which can measure 14 inches and weigh more than 4 pounds, since 2011, as part of a project trapping "non-native" fish.
"You just see these bright golden orange things start to float up," said Christine Ngai, a team member from UNR. "Then you take a net and scoop it up and it's like, 'It's a goldfish!'"
Ngai told Reuters between 50 and 60 goldfish a year have been removed from Lake Tahoe since 2011, but that their ability to multiply requires the population to be monitored heavily.
"Goldfish are very good at getting what they need," she said. "They can potentially compete with native fish for food, vegetation and bugs."
Scientists believe many of the goldfish are introduced to lakes and streams by people discarding them from their fishbowls.
Ngai's colleague, Sudeep Chandra, told the Los Angeles Times the goldfish also pose a danger to the lake's ecosystem, as they prey on fish native to the area and "excrete nutrients that are kind of in the ratio of Miracle Gro," which can prompt algae growth and disrupt the lake's waters, which are known for being crystal-clear.
Watch KCRA's report on the goldfish infestation in Lake Tahoe, aired on Wednesday, below.