1. 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.
2. When adding particularly aggressive fish to your aquarium, it is a good idea to move around the rocks and such in the aquarium before placing the new fish into the aquarium. Moving the rocks in the aquarium will allow the fish to go back and stake out their own territory.
3. Cloudy water is normally a sign of overfeeding your aquarium. Judge the right amount of food to place in the aquarium to not leave too much residue due to overfeeding.