1. Having a quarantine tank on hand is a very good practice to use if you frequently buy new fish. The quarantine tank will weed out any sick fish that could possible get into your aquarium and cause harm to the other inhabitants.
2. You need to have some healthy natural bacteria to process the wastes and chemicals in your aquarium. This will take around 4 weeks to grow naturally, but you can purchase products to speed up the process.
3. You should keep plenty of water testing kits for your aquarium. Testing kits can measure the levels of harmful and beneficial chemicals in the aquarium. You will need these testing kits for the frequent water changes for your aquarium.