“Please do not release your pet goldfish into ponds and lakes!” City Say On Twitter. “They grow bigger than you think, and cause water quality to deteriorate by destroying bottom sediments and uprooting plants.” The post has been shared thousands of times.

Two Canadian ecologists say this situation is part of a larger trend that is happening north of the border.

Jennifer Bowman, an aquatic ecologist at the Royal Botanic Gardens in Burlington, Ontario, said the number of goldfish in the Great Lakes “has indeed increased dramatically since 2015.” “The situation got worse. When they got together, they were very successful; a few goldfish can enter the pond, and you will have thousands next year.”

In a swamp near Hamilton, her team counted 2,000 goldfish. She added that they “are more tolerant of some chemicals in the water that will affect our local fish,” she added, which allows invasive species to proliferate.

Nick Lapointe, a conservation biologist at the Canadian Wildlife Federation in Ottawa, said that dumping unwanted goldfish into nearby lakes or streams seems harmless, but these invasive pets are destroying the local ecosystem. Make the once clear lake brown and muddy. Advocacy group.

Lake ecology

As bottom feeders, they agitate mud and sediment at the bottom of freshwater lakes. He said this makes the water clouded and makes it more difficult for plants and local fish to thrive there.

“In the worst case, you will go from a clear lake dominated by plants to a muddy lake dominated by algae.”

“Goldfish can be more than a foot long. They eat fish eggs and snails and compete with our native species,” Lapointe told CBC News. “We have about 180 aquatic invasive species in the Great Lakes [alone] Each one adds problems and changes the ecosystem. ”

Watch | Huge destructive goldfish occupy Canadian waterways:

Lapointe said there is no data on the number of goldfish dumped in lakes and rivers every year in Canada. However, these numbers are considered important.

In Montreal alone, approximately 10,000 ornamental fish are released every year. 2008 research Published in the Canadian Journal of Fisheries and Aquatic Sciences.

Lapointe believes that Canadians today may be more aware of the danger of dumping aquarium pets into freshwater ecosystems than they were 30 years ago.

But as the population grows and more goldfish are sold, he said the numbers in lakes and rivers will almost certainly increase, especially considering that these creatures now reproduce themselves in the wild, and usually at the price of other species.

He added that most goldfish are not actually golden-this is a rare genetic trait similar to albinism. He said that when goldfish reproduce in lakes or rivers, their offspring are more likely to be brown.

“The decline in freshwater biodiversity is a crisis,” Lapointe said. “The main reasons for this are: climate change, habitat loss and invasive species… We are starting to see more and more a standard list of five to six species that can be seen everywhere.”