It's 4am , and I just went downstairs past my tnak to find my angelfish exibiting some odd behavior. at this hour they would usually be stationary in the tank. But i went down there to find them floating backwards and suddenly darting around. they are bumping into eachother and seem to be breahting heavily. all the other fish in the tank seem fine and are acting normally. tomorrow if they are still doing it im going to take a video. i did my 10% water change as usual today and everything was fine.