The fish were at risk of decimating the frog population in Vinegar Pond in Mousehold Heath when they mysteriously appeared.

It prompted the heath's maintenance team to take a “nuclear option” of draining the pond to clear it of the killer carp.

But the fish have believed to have been spotted in the nature reserve’s waters again.

The fish were removed from the pond last year(Image: Gary Champion)

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Green councillor at Sewell Ward said: "When we........

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