If he started laying on his side he hasn't long to go, they do that when they are dying, if he looks in distress and pain i would end his misery, sorry.
I really hope your goldfish pulls through. If you do have to euthanise him though, please don't take the advice given before. It's been debated on this forum many times, and most of the time the outcome was that it's not a nice way for them to go.
I euthanised him. It was too awful to watch him led on his side at the bottom of the tank gasping for breath with his skin hanging off in flaps... I hope i did the right thing.. I dont think he could have recovered from it...
You did the right thing he was suffering, he wouldn't of got better, you tryed to get him better, thats what you have to tell your self, sorry for your loss, R.I.P. little fellow.
We were checking the fish over this morning when we fed them and it looks like another one has it We've taken him out and i am treating him the same as the last one. Its nowhere near as bad as the other so hopefully we can save this one...