One of my little guys just developed this air bubble that hangs out in his gills I dont know if its a developmental flaw that just showed up or trauma to his gills. There is this bubble that when ever he breathes surface air it makes this bubble that is visible under his gill plate and if it pops he looses buoyancy but with it he tends to float. He has had it for about a week I tried treating with epsom salt and it helps a little but not really. The temp is 80* F and has a water change every other day 100% idea?