Hhhmmmm....It's sounds like one of three things Logic...
Constipation...treated by fasting and pieces of cooked frozen pea, skin removed.
Dropsy...not much you can do, it's always been fatal with any of my fish who had it. If that's what it is he will swell up to the point where all his scales begin to pop out. They either go fast with that or linger for awhile but eventually sucumb.
Underdeveloped swim bladder caused by overfeeding as a fry...nothing you can do about this either, but it isn't painful, just sort of a handicap. If this is what it is you don't feed him too much at one time. 3 or 4 very small feedings a day so that the stomach doesn't bulge against the swim bladder and cause his balance to be even worse than usual.
Have you done any online research Logic ? If there is something else out there that can cause swim bladder issues I don't have any info on it. Those I mentioned are only the issues that I have had to deal with so I know something about them.
Try this site, maybe you can find something there to help...
http://www.fishyfarmacy.com/symptoms.htmlAll the best Logic..and sorry we don't seem to be helping much...