RTGG have vicious teeth and will & do kill there own when small, I've had 4 which lived in a 180gal tank with other smaller and more passive fish. The ones they didn't like they just KILLED straight out. The other they tolerated until they wanted to kill them and then did. I even had at one point a 17 inch Aust Aro in the tank and had to remove it because the dominate male decided to ripe it apart one day. If I was at home right now I could post pics of there teeth and grind plate. Instead of normal type teeth they have dog like teeth, all of which come to a point.