hi guys one of my discus is acting funny,it refuse to eat anything and he is breathing hard with gill covers widely opened,also he is not in the group.the tips of the gills are white colored. I was out the whole day yesterday and when I came home last night I noticed the temp droped from 86 to 80. I am asuming there was a blockout when I was out. could it be a cold or something? please help!