Does anybody have any suggestions as how to ease a swimbladder problem , for a very small , but much beloved pearlscale goldfish ??

I have treated him for constipation (epsom salts, and the pea treatment) but these all passed though him , so thats not the problem. I'm currently on the 6th day of a 12 day treatment schedule using an interpet remedy. It is safe to say that this poor little sod was a merciful rescue on our behalf, as he is deformed to the point where he should have been culled as a fry (horrible to say yes, but true). He is as wide as he is long, and hasn't grown since he was purchased just after new year, i could fit him under a 50p piece,whereas his brother has come on in leaps and bounds. I'm praying it isn't genetic(thou i almost know so in my heart), trying to get down from the surface is exhausting him, and i havent seen him eat for over a week now

. Im not giving up just yet thou, so any suggestions welcomed!!!