Let me preface this by saying that i am not an expert. My yellow eye had the same thing happen, and i didnt want to further stress it out by catching and quarantining, so i kept a close watch and it cleared up after about a week on its own, fish is healthy as ever. It never got cloudy, and i attribute the popeye to an injury, like hitting a rock. it is a goon and always chasing around with the scopas. (they both seem to enjoy it and hang together, not bullying) But, if it is a bad bacterial infection you can risk the fish loosing its eye.