I have 4 baby cichlid fishes in a 5 galloon tank, with rocks, and plenty of plants. I notice abnormal behavior in one of the yellow ones I have. First off, he stays in the water vertically with his tail on the bottom, and his head on the top, when he swims it seems as if he's weak and runs into things, and was swimming kind of sideways. he is actually just staying in one area at the moment, but i also notice around his eyes are starting to turn black. please help me. i dont know what to do.