When fogging machines and larvicides fail, release the guppies. Bidhannagar Municipal Corporation has started releasing guppy fish in the gutter channels as they feed on mosquito larvae.

At a meeting held at the corporation office on November 14 between councillors, health officials and the municipal commissioner, this was decided as a measure to prevent the spread of the dengue.

“Guppies are being released into stagnant water to eat up the larvae. This predatory fish multiplies five-fold in 10 days. So we are hoping the fish population will check larvae growth. This would be the beginning of a natural way of eliminating mosquitoes,” said a health official at the corporation on Wednesday.

Larva-gobbling guppies had been released in countries like Brazil to stop mosquitoes from spreading Zika too. And old-timers in Calcutta remember how guppies could be found in drains even in the mid-80s but are scarce now.

“I have released guppies into various gutter channels in my area and other councillors could replicate the move, if required,” said Subhas Bose, councillor of Ward 6 in Rajarhat.

“Awareness would also be raised. Leaflets bearing dengue dos and don’ts would be distributed by Asha Karmi workers, who are salaried employees under the Integrated Child Development Services. They will be visiting homes and alerting residents,” he added.

Salt Lake hardly has any open drains and is cleaner than neighbouring areas like Dum Dum and Rajarhat. So replicating the move might not yield similar results here. “Introducing guppies would be effective in stagnant water. But most of the water in the gutter channels of Salt Lake is free-flowing. We shall check for gutters with stagnant water and then decide if this is a viable option,” said mayor Sabyasachi Dutta.