A pensioner has admitted using motor oil and detergent to kill his neighbour’s Koi carp and destroy a water pump out of “sheer frustration and lack of sleep”, a court has heard. On Tuesday at Willesden Magistrates’ Court, Duffy pleaded guilty on the day of his trial to damaging the pond, fish, water pump and pipes in March. In mitigation, Elliott Stern told the court his client had tried to deal with the dispute without resorting to killing the fish. “They initially said they would stop the water pump going but then turned around and said that’s not good for the fish.” “Out of sheer frustration and lack of sleep, Mr Duffy, out of character, I would say, lost his mind and committed various damages,” said Mr Stern.