My Albino channel cat, who is now over 14 inches long and as wide as a bottle of poland springs water, is causing all types of problems for the other fish in the tank when the lights go out. He practically stays in one spot during the day when the lights are on but as soon as they lights go out, he's on a seek and destroy mission! He mouths the Oscars and splashes water all over my wall. He's actually moving rocks and slamming into the walls of the tank with such force that I'm afraid of what the next few months will bring as he gets bigger. The only fish that he doesn't DARE pester is the Black shark. Anyone have any idea on how I can calm the bully down?