For the most part, they are drained by toilets or dishwashers and end up in sewers and then in the sea or a nearby river. Now, according to studies they are invasive species and have become a danger to local populations: they can reach the size of a football and weigh up to 4 pounds.
4-Pound Goldfish Shocks Locals In Minnesota
The common household pets can grow far bigger in the wild and cause major disruption to ecosystems. The city of Burnsville shared images showing several monster goldfish caught during a survey of Keller Lake.
They feed on the eggs that other fish lay and when searching for food they use a technique consisting of shaking the ground. This activity presents a great problem since when the mud gets lifted from the bottom, buried nutrients float, resulting in a large growth of algae.
According to a study carried out by the University of Canberra, during one year they followed 100 specimens, which achieved a migratory transfer of approximately 155 miles from the starting point.
The study determined not only their resistance to long travel stretches but also their high reproductive capacity once they have no space limitation.
The recommendation of the experts is if people are not going to keep the fish, they must be taken to an aquarium because they can become “monsters”.
Minnesota wildlife officials have been dealing with a similar problem in nearby Carver County, where 50,000 goldfish were removed from a creek in October last year.
It is a species that has been in the West for many years, but its origins are transferred to China, wherein the natural habitat they collaborate with the ecosystem to strengthen it, today in ecosystems that are not prepared to receive them, they are a threat to the health and fishing of the areas near rivers and lakes.