I don't know if something is wrong with him, or if this is just a sign of him being healthy and active. He's swimming in circles. I even saw him do a flip. (In the water... he didn't come out.) He's just swimming around and around in little bitty circles. Not around the tank... he goes from the bottom of the tank up and back around... that's where the flip came from. Does this mean he's just healthy and active, or is something wrong?