Many people with aggressive, territorial fish are lulled into a false sense of security when their fish are juveniles, because the fish don't show their true colors until the reach maturity. Then, all of a sudden, you find a fish dead and floating, or severely beat up and requiring separation from the others. This can be a particular problem because it's often hard to find homes (with LFSs or elsewhere) for adult fish. That's why it's so important to learn about your fish before you stock or at least before they reach adult size.
Don't develop a false sense of security because your fish get along now. You'd be amazed at how quickly that can change.
Good luck,
Jim