Exotic aquarium fish species threatening lake biodiversity

Three dead Alligator Gar discovered in Neknampur Lake

March 22, 2021 11:58 pm | Updated March 23, 2021 10:49 am IST - Hyderabad

Red eared terrapin, an invasive turtle, is also being left in city lakes.

Red eared terrapin, an invasive turtle, is also being left in city lakes.

Discovery of a fish species called Alligator gar in Neknampur Lake has set the alarm bells ringing for the biodiversity of city lakes.

An NGO ‘Dhruvansh’, which has adopted the Neknampur Lake, has discovered three dead members of the fish species in the lake and raised concerns about the same, because they are not native to India. “These fish are not found in Indian rivers and lakes. They are grown for aquariums, and when they become too big to handle, people leave them in lakes,” said conservationist and lake activist Madhulika Choudhary, the founder of Dhruvansh.

Alligator gar are naturally found in North America, and brought here for sale as aquarium species. They can grow up to several feet in length, which eventually makes them unfit for aquariums. That is when the owners and aquarists, unable to house them and feed them any more, leave them in city lakes.

“We found three, because they are dead. We don’t know how many such fish have been left in the lake. They are predatory in nature, and can wipe out the entire lake of its biodiversity,” says Ms.Choudhary.

Farida Tampal, State Director of WWF-India, says aquarium species being left in city lakes has become a menace of late. “I have come across an instance where an Alligator gar was left inside the Lotus Pond. There is no control over which kind of fish are being brought from outside and where they are being left. Evidence suggests that even extremely predatory species such as Piranhas which are being grown by aquarists here,” Ms.Tampal says.

Another invasive species which is being found in city lakes is the Red eared terrapin/turtle. “A member of this species was found in Neknampur Lake earlier. They are aggressive in nature and kill other pond turtles such as pond terrapins and flapshell turtles. Exotic species are dangerous for native ones. If you can’t care for them, why do you keep them,” asks Ms.Choudhary.

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