Sonya Miles, the veterinary surgeon who operated on him, told AFP on Tuesday that the five-year-old fish first had to be put to sleep and taken out of the water to remove a tumour that had grown as big as him.
“There was one hairy moment when its heart stopped but it started again thanks to the exotics nurse,” she said, referring to her colleague at a veterinary hospital in Bristol.
The operation, which took place earlier this month, lasted 45 minutes. Nemo was subsequently returned to the water where he began swimming normally.
Nemo’s owners, a couple, also have three cats, two dogs, a hedgehog and a parrot, British media reported.
The case made national headlines on Tuesday and there were strong reactions on news websites.
“I would have done the same and am very glad to hear that there are surgeons who are able to operate on little lives like this,” said Martina Watson on the BBC’s Facebook page.