Hello I have a reagal angelfish that i've had for a year or so. Always eating everything I've thrown in there. It's tank mates are two puffers and a clown trigger. Recently after I added a few fish it stopped eating. There has been plently of food in there and it doesn't seem interested. I haven't noticed any aggression towards it however I did see which looks like a nipped fin. Anyway I am stumped. I did see white stringy poop coming out the other day. So is it possible I have an internal parasite? Currently I have the fish in a quarantine tank and it looks and seems perfectly healthy. Any suggestions?