Fish tank lighting is an imperative part of your tank set up. Of course you want to be able to see the fish and other life in your fish tank, but light is also important to the health of your fish and plants. For example, without the correct light, corals cannot survive even with the best treatments and food. In planted tanks in particular, light is necessary for photosynthesis to occur. Without it, plants will fail to thrive and grow. The best formula is to emulate natural periods of light, with up to 12 hours of 'day' light and the same of darkness (depending on your set up). Where as not enough light can cause problems, too much can encourage the growth of algae and murky water. So it is important to get the balance just right.
In a tropical or reef tank, coloured lighting is important to enhance the natural colours of your fish and corals. Bright white, blue and even red show the beauty of plants, fish and reef life to their best advantage. Using such lighting can encourage growth of healthy organisms in the water, which in turn improves the appearance and health of your tank.