Whats wrong with my true percula clownfish?

upside down swimming is a sign of stress. try buying some "stress coat" available at walmart. my bubble-eyed goldfish did that when i moved and he ended up dying 3 days later. their swim bladders get screwed up when they get stressed. my clownfish is swimming in a panic as of lately also and not eating. i just moved his tank. if your clowny doesn't get better within a week, go back to the pet store and talk to the people there. mines' a locally owned fish store and the owner is amazing! very very helpful!! otherwise test your water's pH, nitrite, nitrate, chlorine, salinity, the works. oh, on another note...my striped damsel was the aggressive fish in my tank, he attacked my clownfish and my other fish (i forget what he is, but he's a lil blue guy and was really cheap too). so maybe your damsel is provoking some stress. try to put a tank separater in for a day or two and see how that goes. keep the fish separate. if you can't find a screen, try a spawning net or isolation net and put one of the fish in there until they get used to it. good luck!!!