Mousehold's Vinegar Pond drained because of invasive fish

Vinegar Pond, in Mousehold Heath, was emptied to remove more than 6,000 goldfish and koi carp that had been mysteriously put into the water.

The draining was carried out by the heath maintenance team to stop the fish from "decimating" the local frog and newt population.

The whole of Vinegar Pond was emptied to remove the fish (Image: Gary Champion) Gary Champion, Sewell ward councillor and a member of the Mousehold Conservators Committee, said: "This decision was not taken lightly and follows two previous attempts at removing the fish using electrofishing, which stuns the fish and allows them to be caught.

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"Unfortunately, as the expression goes, some fish kept slipping the net."

According to Cllr Champion, the goldfish and koi were introduced to the pond at some point in the last several years, likely during the Covid lockdowns, where they have since bred out of control. 

The goldfish and koi crossbreeds defied all odds and continued to breed (Image: Gary Champion)

 This is unusual, he said, because any offspring between the two are supposed to be sterile. 

When born, some would be born brown or grey and turn orange as they get older.

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Cllr Champion said: "We thought they would breed themselves into extinction but their numbers have grown instead.”

After the water was removed from the large pond, the fish were taken to another park where they would pose no threat to frogs and newts. 

Sewell councillor Gary Champion praised the work of the heath wardens (Image: Newsquest)

"Vinegar Pond used to be known for the sheer numbers of frog spawn but the koi crossbreed has nearly wiped them out," Cllr Champion added.

"Now that they're gone, we hope that the frogs will have a fighting chance next spring.

"I would like to thank the wardens who work tirelessly to maintain Mousehold Heath, an area close to my heart and of importance to so many people in our city."

The fish were taken elsewhere where they would pose no further harm (Image: Gary Champion)