Hmm, I'm a bit of a newbie, but maybe try a little bit of aquarium salt? It helped with my betta's Ich and cleared up a cottony-spot he got on the side of his head. It's not really a med, and it doesn't hurt the fish if you don't use it for more than 10 days straight.
When my fish had Ich, I added aquarium salt and cranked the water temperature up to 82-84. I realize your fish doesn't have Ich, but maybe keeping the water at around 80 and adding salt will help?
Just be careful with raising the temp if you suspect bacteria is what's making your fish ill, cause some grow faster with extra heat
My fish responds really well to salt treatments, he really seems to perk up when I add it to his water when he's feeling bad.
Good luck with your fish!
Edit:*facepalms* You're already using salt, oops!