1. You should keep some brushes on hand, especially if you are a reef aquarium owner. With your brushes you will be able to clean off any built up grime from inside your aquarium or on the surfaces of your hard corals.
2. Pay close attention to your fish's PH needs and augment your aquarium as necessary to accommodate the new fish you are adding to your aquarium.
3. You should always research the different types of fish you are going to be housing together. Certain fish can be extremely aggressive and cannot be paired with other fish of different temperaments.