The man took his three-inch pet to the vet after noticing that it was struggling to poo properly – but that turned out to be just the fin end of the wedge. The man – a company boss – went green around the gills when the scale of the problem was explained to him, and initially rejected the £300 cost of delicate surgery on the fish’s backside as a bum deal.

But within 10 minutes the soft-hearted owner changed his mind and brought the ailing fish back to the surgery in north Norfolk to undergo the costly operation.

Vet Faye Bethell introduced a carefully measured anaesthetic agent into the fish’s water. The pet was then removed from the tank, and had anaesthetic water put into its mouth via a tube and bubbled over its gills. Faye, 29, then used tiny instruments to remove one lump close to the fish’s anus (yup!) and another from the dorsal fin.

The 50-minute procedure all went swimmingly, and the much-relieved goldfish was returned to its tank, handed back to its owner, and then restored to its rightful place in the man’s office.

Faye, of the Toll Barn Veterinary Centre in North Walsham, Norfolk, England, said the surgery had saved the fish’s life.

“I have never done a procedure like that on a goldfish, although I have done it before on more valuable fish like a carp,” she said, as reported in the Daily Telegraph. “The actual surgery is quite straightforward but administering the anaesthetic is quite complicated.

“The issue was the fish couldn’t poo and it would have eventually become toxic and it would have died. There was nothing special about the fish. He just liked it a lot. People love their pets – but that was an expensive little goldfish.”

Goldfish – which cost about £3 – can live for up to 10 years. This one was nearly three when it was given its new lease of life.

The Toll Barn practice opened a year ago and specialises in exotic animals and unusual pets – Faye’s work over the festive season included castrating a skunk.

It’s not the first time a goldfish has undergone expensive surgery to save its life. It happened Down Under last year when Melbourne vet Dr Tristan Rich performed delicate micro-surgery to successfully remove a large tumour from the head of a 10-year-old goldfish called George. Er, yes… what was all that about tough, unsentimental Aussies?