In my 400, I have both a zebra and blue ribbon. They are both well behaved and bother none of my fish. They are well trained on feeding days when I turn off the return pump and suspend the tunzes, they both creep out and work upto the surface looking for grub. Even my blue ribbon is eating frozen foods and looking very good. I originally added my zebra as I had at least one rogue crab in my tank. I found the molted claw of a stone crab and knew in time, fish would disappear. Enter the zebra and he's restored order in my reef. Ain't crabs hidin' now.