1. When keeping aggressive species of fish, it is best not to introduce peaceful species of fish among them. Aggressive fish will tend to bully the more peaceful fish. Make sure to thoroughly read about the compatibility of the selected fish for the aquarium.
2. It is important to pay attention to the limitations of the fish you place in the aquarium. Do not place fish into aquariums smaller than there recommended range, this can lead to increased aggression and decreased health.
3. When adding plants to the aquarium, be sure to check the lighting needs. Try to find plants that will fit the pre-existing lighting conditions of your aquarium. You should avoid plants that require much more light than the fish in your aquarium.