1. When starting out a new aquarium, it is best to add hardier species at first. Once your aquarium ages a bit and gets settled, you can start to add more sensitive fish to the aquarium.
2. You must always treat the water in the aquarium before attempting to place fish. If you fail to treat the water the fish can die from the condition of the water.
3. Try to provide an environment that is as stable as possible, fluctuations in the aquarium can have a negative impact on the aquarium. Try to keep the temperature and PH levels fairly balanced in your aquarium.