1. Catfish sometimes require freshwater as juveniles and then as they get old they will need a more brackish environment. Make sure you read up on your catfish to learn what its needs will be when it gets older.
2. Avoid placing your aquarium near a radiator or any other form of heater. The heat given off by these devices can easily upset the temperature balance in your aquarium. Raised temperature levels can kill off the fish and plants that you have in your aquarium.
3. Goldfish can live incredibly long periods of up to 25 years. You should plan accordingly when you purchase a goldfish.