Maintaining good water quality is the single most important thing that aquarium owners can do to ensure the health of their fish. Poor water quality is probably responsible for more aquarium fish deaths than any other factor. Learn the keys to optimal filtration and pristine water conditions. Remember, also, that the amount and quality of light can make the difference between a healthy, aesthetic aquarium, or a disaster. Different species have different requirements for lighting intensity and wavelength. Finally, learn about other equipment that will help provide the proper conditions, and how to test your water and correct any problems.