Giant goldfish found in US lake prompts plea to pet owners

A city in the United States has urged people not to dump their pet fish in the wild after giant goldfish were found in a lake.

Keller Lake in Minnesota has become home to some huge goldfish that officials say are disrupting the water quality.

The supersized goldfish caused a splash online after the City of Burnsville posted images of them on social media alongside a plea for people to stop putting their fish in the lake.

A post on the the city's official Twitter read: "Please don't release your pet goldfish into ponds and lakes!

"They grow bigger than you think and contribute to poor water quality by mucking up the bottom sediments and uprooting plants. "Groups of these large goldfish were recently found in Keller Lake."

Minnesota conservation officials say other ornamental and pet fish found in the state's waters include koi, pacu and piranha.

A member of the carp family, when kept in small indoor aquariums goldfish tend to stay about grow no longer than 5.1 cm.But in the wild they can grow far bigger. In July 2010, a goldfish measuring 41 cm and weight five pounds was caught in a pond in Poole, Dorset.

Contrary to popular belief, goldfish are not quite as stupid as we are led to believe.

They have a memory-span of at least three months and can distinguish between different shapes, colors, and sounds.