Yesterday morning I noticed my Melanarus wrasse laying on his side on the sandbed and breathing rapidly for a period of time then getting back up and swimming around again. His mouth is constantly wide open, but he still has an appetite and is eating normally. His stomach and sides looks full and he has normal poop. Physically, he looks completely normal. No signs of ich or velvet spots and his gills aren't inflamed. No other fish are sick and all parameters are normal. He woke up from beneath the sandbed a bit late today and seemed to be better. He was swimming around much more and was sitting upright on the bottom instead of on his side. He's still breathing faster than usual though and his mouth is still open. Does anyone have any advice? I have a QT ready and several medications but I have no idea what I should treat him for.