Burnsville officials are urging residents to think twice before releasing a pet fish into local waters after groupings of giant goldfish were pulled from a local lake this month.

A recent fish survey conducted on Keller Lake found groupings of invasive goldfish, which city officials say have been observed on the lake in recent years.

Photos of the hefty fish made a splash online.

“Please don’t release your pet goldfish into ponds and lakes,” the city of Burnsville urged in a Facebook post. “They grow bigger than you think!”

Goldfish, a member of the carp family, find themselves pretty comfortable when introduced into Minnesota’s waters, presenting a host of problems for native aquatic life.

City officials say large populations of goldfish contribute to poor water quality by mucking up the bottom sediments and uprooting plants.

These disturbances also make it harder for native fish to feed.

“Instead of releasing your pet goldfish in a local lake or pond, please consider other options for finding them a new home like asking a responsible friend or neighbor to care for it,” the city wrote.