I got a small flame angel a few days ago and he seems super healthy and very active but I saw him poop one time and there was like a white cloud and a long white thing came out that was stuck to him for a few seconds then fell of and I heard that’s bad. Lfs said he was just feeding brine shrimp but I feed him brine shrimp and ocean nutrition prime reef flakes but he stopped eating flakes for some reason. I have other fish in my tank and I don’t want anything to spread so I really need some advice asap. Also the long white thing went in my filter so should I clean my filter out?