Last night I thought that my nova star cushion (I'm not quite sure about the name). From the glass side, it looked like he was splitting in half. I couldn't quite tell from the tank side. This morning, he moved to the other side of the tank, still on the glass, and is almost totally "torn" in half. I can see meat. I have no aggressive fish, no one is bothering him. He is still holding unto the side of the tank. Can anyone tell me what is happening? Thanks