Well my big ray(17 inch disc) always likes to swim up the sides to the top but now he added a twist.He figured out how to splash water and make an incredible gurgling sound when he gets to the top of the tank.Now its even worse two of the Motoros have joined him.I am afraid all 6 rays will be doing this soon.Is this normal?They are in a big square shaped tank of 450 gallons and only ever seem to use half the tank at best.They mostly just all stay at the front of the tank and be obnoxious like begging puppies..Does anyone else have rays like this?