I got Dougie about 2 months ago and a little after that noticed what I could only describe as a rash on top of his mouth and kind of around his eye. It didn't seem harmful so I left it alone but kept a close eye on it. I asked the friend who was with me if that rash had been there when we got him and she said yes. I went home for a weekend leaving his feeding to my roommate but when I came back his rash was terribly worse than when I'd kissed him goodbye a few days prior. I have no idea what it is--he's acting fine, hasn't been rubbing against things any more than he usual does, is eating normally and still reacts to me very well--and all these diseases I've read about are terrifying me. I love my little Dougie to pieces, I don't want him to be sick!
He has a filter but no heater, no air stones or anything like that either. He eats twice a day, Tetrafin flakes, in a 1gallon tank (Aqeuon MiniBow 1). I change his water pretty much 100% every week. He has no tank friends. Please let me know if changing his water like this is a bad idea also. I don't want to stress him out.
Any advice would be golden. Doug and I thank you guys for your help!
Here's some pictures: