Unwanted Pet Goldfish Dumped In Lakes Grow Into Giants

Unwanted Pet Goldfish Dumped In Lakes Grow Into Giants

City officials warn people not to dump goldfish as they please in water bodies and instead find other homes with a responsible friend or neighbor.

Image Source: Facebook/City of Burnsville, Minnesota - Municipal Government

Goldfish are known for their tiny stature and fitting well into home environments. But when they are released into outdoor environments like ponds or lakes, they turn into a menace. The city officials of Burnsville, Minnesota have shared a warning about releasing unwanted goldfish into the city's ponds and lakes. Sharing images of gigantic goldfish, they have stated that they are wreaking havoc on ecosystems. The goldfish in the pictures are the size of a football or even bigger. Pet goldfish become an invasive species in the lakes and the municipality of the City of Burnsville is urging people to not dump goldfish as they please in water bodies.

In a Facebook post, they wrote: "Please don’t release your pet goldfish into ponds and lakes. They grow bigger than you think! We recently partnered with the City of Apple Valley, MN, and Carp Solutions to conduct a fish survey on Keller Lake to assess populations of invasive goldfish and other fish in the lake. Large groups of goldfish have been observed in recent years on the lake. At high populations, goldfish can contribute to poor water quality by mucking up the bottom sediments and uprooting plants." They shared pictures of goldfish that were caught during the recent survey.


The officials even suggested that people consider finding a new home for their pet goldfish, with a responsible friend or neighbor who could care for it instead of releasing them into a local lake or pond. Caleb Ashling, Burnsville’s natural resources specialist told the Washington Post, "You see goldfish in the store and they’re these small little fish. When you pull a goldfish about the size of a football out of the lake, it makes you wonder how this can even be the same type of animal." This usually happens when a species is introduced to an environment and they tend to outcompete native species and destroy their habitat.


“They seem to be getting more and more widespread,” Przemek Bajer, an aquatic invasive species professor at the University of Minnesota and who also owns Carp Solutions said. “You think about how many of those fish are sold nationally and how many are being released. That’s a pretty big vector of introduction.” They tend to reproduce rather quickly and are also surprisingly resilient. They can survive for months without oxygen and also withstand extreme cold and hot temperatures. “People are trying to be nice, but they don’t realize that goldfish can really have a lot of unintended consequences,” Ashling stated. “Most people really care about their lakes and ponds, but you may be causing problems you weren’t aware of if you let them go there.”


The goldfish problem is not new. The disaster they were creating was noted in 2016. The same problem was noted in southwestern Australia. The impact of someone having dumped unwanted goldfish in the creek was noted two decades later but researchers from Murdoch University have been studying the phenomenon since 2003, reported The New York Times. The same goldfish outbreaks have been reported in Nevada, Colorado, and Alberta, Canada, in the last several years. Damage control and trying to eradicate goldfish is a notoriously difficult undertaking once the goldfish become established in the environment.


The paper published by the researchers from Murdoch University helped fill in the dearth of information about the consequences of domesticated goldfish taking over local water ecosystems. "The results of this study strongly suggest that Goldfish (Carassius auratus) undertook a spawning migration into a lentic habitat. These results have important implications for developing control programs for the species, such as targeting connections to off-channel lentic systems during its breeding period," the study concluded at the time.


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