As the title says, my blotchy anthia was has been doing great since I introduced him to the tank 3 weeks ago. Eating and swimming around. Yesterday I did a water change and noticed that he didn’t come out. Saw him wedged under a rock, still breathing,(but maybe breathing hard? It’s tough to tell with him under the rock) today it’s more of the same except in a different spot. Did the water change traumatize it or should I be thinking some sort of disease? All the other fish including 2 clowns, a kole tang, a possum wrasse, and a Randall’s Goby are all acting totally normal