I got a false percula about four days ago, and for the first two days, he was swimming up at the top,and around the tank, not acting unusual. But today, i noticed that he was laying down on the sand. He would occasionally get up and swim a little bit, but compared to his previous behaviors, the swimming he does now looks harsh and forced, and difficult for him. he is swimming a bit slower, and for short periods of time. At one point he was laying completely on his side.(Note, i do not know if he is a "he" specifically) I checked for white spots and i haven't seen any. My other fish are acting fine, if not better( one fish was cowering in the side when we first got him, but now he is swimming about normally) i have two fish and a cleaner shrimp. One peice of dried coral and barnacles as decoration/ rocky things. No coral or anemones yet. I'm worried he is getting sick. Insight?