I have just noticed that my goldfish is extremely bloated and is sitting at the bottom of the tank quite a lot of the time. Also, I know this sounds funny but it's bum is always open (lol sorry). What's the problem?
Have you only got one goldfish? Perhaps it's lonely. If you had more than one I would have suspected pregnancy, that's if goldfish get pregnant. Sorry, I'm not being much help, but I AM interested.
I have had a couple of fish die with swimbladder even though I tried the peas and medicine from the pet shop.
My daughter had one die recently. I don't know any that have survived this but I am sure someone more experienced has managed to get their fish recovered.