sounds like cotton wool? fungus i think, and congrats if that was it you did a real good job nursing him back, but continue with the meds till its completly gone, very clean water is key, most fishes that get that die, a magior fry death problem but mostly i think spawn water needs to be cleaner, but no matter what i tell some people,,, ie dumb pets shop owner that should just stick to sales cause he is such a nube that he was keeping bettas with goldfish,,,, anyway sorry bout the rant! be your guys seem to be getting better!