1. When adding new species to your aquarium, you have to ease them in. Adding too many fish too quickly can cause the ammonia and chemical levels to raise quickly. Adding fish slowly gives your filter time to catch up.
2. 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.
3. You should always stay up to date on the new and exciting practices for fish keeping. Subscribe to several news letters to keep up to date. If you like to read, go to your local library and get some books on fish keeping.