Man, 76, admits killing neighbour's Koi carp fish with oil and detergent - blaming 'frustration and lack of sleep'

By SHANNON MCGUIGAN, NEWS REPORTER and ELEANOR MANN Published: 12:00, 4 August 2026 | Updated: 12:22, 4 August 2026 A man has admitted using motor oil and detergent to kill his neighbour's fish and destroy a water pump out of 'sheer frustration and lack of sleep', a court has heard. Gerry Duffy, 76, of Barnet, north London, was 'driven completely insane' by the sound of a water pump running his neighbour's fishpond. At Willesden Magistrates' Court this morning, Duffy pleaded guilty on the day of his trial to damaging the pond, fish, water pump and pipes in March.  He had warned his neighbour, Andreas Ptohides, that he would take matters into his own hands if he did not do something about the noise.  But after the dispute over noise, the former builder sloshed motor oil and cleaning detergent into Mr Ptohides' pond containing Koi carp fish.  Four days later, Duffy was captured on CCTV climbing into Mr Ptohides' garden and damaging the water pipes and electric pumps.  Shahid Iftakhar, prosecuting, told the court the 'neighbour dispute' had killed 'five or six' of Mr Ptohides's Koi carp, and potentially caused of damage.  The neighbour claimed £800 worth of damage was caused, Mr Iftakhar said, but today the prosecution stated the damage was £565.   Gerry Duffy (pictured outside Willesden Magistrates Court today) admitted using motor oil and detergent to kill his neighbour's fish The 76-year-old told the court he did it out of 'sheer frustration and lack of sleep' He said: 'The defendant has previously complained to the complainant about noise coming from his garden and has said words to the effect of, "if you don't deal with it, I will" – there was a warning before the incident.' Mr Elliott Stern, defending, said Duffy had been driven ‘completely insane by the noise’ from the electric pump feature on his neighbour’s pond. The 76-year-old and his neighbour had discussed the matter several times, to which Mr Ptohides said he would stop the pump sometimes, he added. However, the neighbour later said he would no longer carry on doing so because it was ‘not good for the fish’. Duffy contacted the council, whose worker visited and said there was no noise, advising ‘he either move[d] or close his windows’, Mr Stern added. ‘Out of sheer frustration and lack of sleep. Mr Duffy out of character and I would say technically lost his mind and committed these various damages,’ the prosecution said. He added that Duffy had been pushed ‘beyond rational thinking and did not think about the consequences’ of his actions. Mr Stern, mitigating, said the pensioner had COPD, as well as several health issues including COPD, type 1 diabetes, skin cancer, and high blood pressure. It was also heard that his health and declined both physically and mentally in the last year, and that he suffered from ‘severe’ anxiety and depression. Mr Stern also added that Duffy’s break up with a partner had also had an impact on him over the last three years. Magistrate Matthew Cornish said: ‘We believe there was some planning given the incidents occurred over three separate days.’ Duffy was ordered him to pay £565 in compensation, £440 for the pond and associated equipment as well as £125 for the destruction of the fish. He was also handed a two-year conditional discharge order, meaning if the 76-year-old committed further crimes over the next two years he could be punished for this one also.