I have to admit that not many people bring their fish to the vet. Bob the goldfish was certainly a very lucky goldfish - not only did he have a huge tank with lots of friends to swim around with, he also had an owner who cared enough for him to seek help when a tumour started to appear on his side. He had a large round mass that first appeared about 5 months ago just below his pectoral fin. It was making it difficult for Bob to swim.
Surgery would be needed to fix him.
I anaesthetised Bob and when he was properly asleep I removed him from the water. A constant drip of anaesthetic over his gills kept him asleep and wet whilst I carefully removed the tumour. I then stitched him up and soon Bob was back in a tank recovering. Whilst he swam around a little drunkenly at first he was soon back to his normal happy self.
Bob recovered well and I removed his stitches three weeks later.
Goldfish are one of the most popular pets but often are badly cared for and many fish die as a result. The myths that fish feel no pain or can only remember things for 5 seconds are untrue and are no justification for not looking after your fish. I often get people asking me why their goldfish has suddenly died - Almost always it comes down to how they looked after their fish. Fish live entirely in their water so imagine how healthy you would be if you were locked in a small room with nowhere for your wastes to get out. To look after goldfish properly you need to do some research but basically you need to get as large a tank or pond as possible, change 10% of the water weekly and get a good filter to create water movement and remove wastes.
Kept properly Goldfish can live for over 20 years.