1. 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.
2. Goldfish require a PH level of around 7.5 to live comfortably. Use PH testing strips to ensure that the levels in your aquarium are just right.
3. You must always treat the water in the aquarium before attempting to place fish. If you fail to treat the water the fish can die from the condition of the water.