Silvers can be pushy but arent that aggresive. Mine cruises and slams into anyone making trouble. They will be the first to eat though. The Ngt's are another story. I keep all of mine together and they constantly chase each other and bite at each other. Nothing really serious except the regular fin splits but if your other dats are not eating or sick they might get really damaged. They are the most aggresive of all tigers. I keep a smaller ngt with around 20 thin bars and they are fine. Just make sure that there is lots of food to go around and a good size community helps distribute aggression. Go for it and good luck.