I woke up this morning to find my Yellow Tang on the sand bottom. Needless to say he died over night. I'm trying to figure out the reason why. I have no aggressive fish or bullies in the tank, he was eating and swimming around fine the night before. When I pulled him out there were no markings or sign of disease. He used to hang out with my Foxface all the time, is it possible he got stung? My water parameters are all good except I've been battling nitrates for the past 2 months, they've been stable around 20, no spikes or anything. Anyone have any guesses as to what happened?

