Are you noticing anything else? Like is he getting paler, is he swelling/bloated anywhere? If you are so sure it is the pH, why not check it? I didn't see where you answered earlier whether or not you tested the pH. I just don't seem to think it is pH...I'm still convinced it's swimbladder. pH shock symptoms I've seen on different websites the fish will lay on the bottom or substrate and not move around...they are lethargic and what not. Have you tried switching conditioners and seeing if there is a change in the way he acts? What kind of water are you using? Tap? Spring?