Setting a pet fish free in a local lake or waterway is not an act of liberation — it’s ecological sabotage.
According to researchers at Australia’s Murdoch University, once pet fish are introduced into lakes and rivers they have the potential to decimate an ecosystem.
While a goldfish or koi might remain miniature when housed in a bowl or aquarium, once freed into a larger environment the fish are able to grow at an exponential rate. They also eat up food that native species depend on and introduce exotic diseases.
A study published last year by Murdoch University’s Freshwater Fish Group and Fish Health Unit claims “introduced freshwater fishes are one of the major global threats to aquatic biodiversity.”
“They are eating up the food resources and using up the habitat that our native fish would otherwise be using,” Jeff Cosgrove, a Postdoctoral Research Fellow at Murdoch University, told the Australian Broadcasting Corporation.
In addition, once they’ve been introduced into a new ecosystem they can be “extremely difficult to eradicate,” says Cosgrove.
Photos: Inside a Hospital for California's Stranded Seals and Sea Lions
A California sea lion sits on the edge of a pool at the Marine Mammal Center in Marin County, Calif. on May 9, 2014.Corey Arnold for TIMECalifornia sea lions swim and sit out in the sun while visitors look on at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEHarbor seal pups wear plastic identification tags that help caregivers tell them apart at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEHerring breakfasts are organized and labeled for each seal and sea lion at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEA harbor seal pup wears a plastic "hat tag," used to identify individual animals at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEA malnourished elephant seal pup looks outside a pen at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEVolunteers tube-feed a malnourished harbor seal pup at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEA volunteer restrains an elephant seal pup while the animal is fed through a tube at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEA shaved patch on the back of a harbor seal shows where blood was drawn during an admit exam at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMESeals and sea lions released back into their natural habitat are added to annual graduation posters at the Marine Mammal Center in Marin County, Calif., May 9, 2014. Corey Arnold for TIMEResearchers perform a necropsy on a California sea lion that died of malnutrition at the Marine Mammal Center in Marin County, Calif. on May 9, 2014.Corey Arnold for TIMEDr. Shawn Johnson, Director of Veterinary Science, listens to the lungs of a young sea lion under anesthesia at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEA California sea lion pup undergoes surgery for a lymph node abscess at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEStudents on a field trip learn what to do if they find a stranded seal on the beach at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMESiobhan Rickert, 18, has been a volunteer at the Marine Mammal Center for four years She is one of a dedicated network of 1,100 volunteers who help run the facility in Marin County, Calif., May 9, 2014.Corey Arnold for TIMEAn elephant seal pup lies in an enclosure at the Marine Mammal Center in Marin County, Calif. on May 9, 2014. Corey Arnold for TIMEThe Marine Mammal Center sits where the U.S. military once had a missile site outside San Francisco, in the Marin Headlands, Calif., May 9, 2014. Corey Arnold for TIME
