I am fairly new to saltwater aquariums and so far it has been going great and my daughter and I have had a great time in the hobby.. However today we came home and I could not find my angelfish. When I did find him, he was hiding under a rock laying on his side. When he came out he would swim either sideways or upside down while curled up. I am not familiar with this and seems to be very odd behavior. I have separated him into a quarantine tank but at this point I don't really know what to do, or what is wrong. Right now he just lays on the bottom and looks like he is trying to curl up into a ball. If anyone has any suggestions etc I would really appreciate it. thanks!