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. Make sure to always keep your aquarium level when placing it. If your aquarium is uneven, the weight of the water can press against the seems and this can cause major problems in your aquarium.
3. Make sure you ask plenty of questions when you are buying accessories or fish for your aquarium. The salespeople are there to help you, and should be able to handle any concerns you have when buying items for your aquarium.