Pet goldfish dumped into a Minnesota lake have swelled into monsters, photos show

Massive goldfish have become an invasive species in a lake in Minnesota where people have released their pet fish.

Officials in Burnsville said last week that releasing pet goldfish into lakes and ponds could wreak havoc on ecosystems.

"Please don't release your pet goldfish into ponds and lakes. They grow bigger than you think!" a post on the city's Facebook page said, adding that they "can contribute to poor water quality by mucking up the bottom sediments and uprooting plants."