So, about 3 days ago I saw a very sudden shift in one of my black skirts behavior. He "traps" the other 2 black skirts in very small pockets of the tank and refuses to let them free. It's like he's putting them in jail or something. There are no actual signs of actual aggression just heavy bully behavior. He does let them eat but I think that's because hes distracted by his own eating. Also, along with his behavior change is his color change. During the "day" hes nearly all white! **** near see through. When I turn on the dark, his color returns a bit and his behavior kinda goes back to normal schooling behavior. The other 2 black skirts don't show any of this at all. there color is normal with normal behavior. He doesn't attack or bully the other fish, just the other 2 black skirts. Any and all advice welcome!!