1. Pay close attention to your fish's PH needs and augment your aquarium as necessary to accommodate the new fish you are adding to your aquarium.
2. It is not considered a good idea to keep aggressive fish with fish of other temperaments. You should keep peaceful fish in an aquarium with other peaceful fish to avoid any sort of fighting between the fish. Aggressive fish should only be kept with other aggressive fish.
3. Always use a new or clean bucket when going through the acclimation or water changing process. A bucket that has been used to hold bleach or other chemicals can be very harmful for the fish in your aquarium.