1. Angelfish are normally very peaceful fish, in times of breeding they can get aggressive. It is a good idea to only keep one pair of mating angelfish in the same aquarium, as more of them can lead to infighting.
2. If you use your tap water, you should make sure to remove the chlorine from the water before you add it to the aquarium. Chlorine can be very harmful to some of the fish in your aquarium. You can purchase kits to remove the chlorine from your aquarium at many retailers online.
3. You should always take the time to acclimate your fish to the aquarium. Acclimating your fish will get them used to the environment of the aquarium. Adding fish directly can be too much a shock for your fish and can pose health hazards.