get either the rectangle or humma, should be fine with the niger as long as the tank is large enough and they are a bit smaller to start PLUS the niger grows REALLY FAST.. maybe try a blue jaw or sargassum if you want a 3rd. Personnaly I have a niger (the largest fish in my tank) with a clown and a humma, not including my kole tang, hawkfish and 2 maroon clowns...in my 150g. in about 2 more years ill have to upgrade cause eveyone will be getting to large to live comfortably..