I'm sorry to hear this but you can take your fish to the vet if you love it that much. I saw something on animal planet about swim bladder can be caused by a tumor. They X rayed the fish. A vet must be certified in aquatic animals.I don't know either. He feeds and is alert and active enough that I don't feel I need to rush to euthanize, but at the same time what quality of life is there to Bob at the top of the tank most of the day? Sometimes on his side
It's been about 2 months. No signs of deterioration in health...other than floating
Good luck just keep doing water changes and try to give bob a nice variety of diet.