In a tank I keep at work I have 3 SilverDollars, 2 Severum, 1 Oscar. I want to put more fish in the tank. The tank is 65 gallons. The goal is big and more colorful, which seems to mean more aggressive. LFS told me overstocking is a good way to lower aggression but I would have to stay on top of water changes. LFS had 2 Veja? and 1 nice Texas that I was considering. Is this a good idea? What are the problems?