aquarium lights

Freshwater aquarium lighting often comes in two forms; one is a screw-in style incandescent bulb and the other is normal output fluorescent lighting. Screw-in compact fluorescent lighting is also used in freshwater aquaria since it provides brighter light output than traditional screw-in style bulbs.
More demanding freshwater set-ups, such as planted freshwater aquariums, may require stronger light sources. Compact fluorescent bulbs, high output T5 bulbs or metal halide lamps are often used over such aquariums to encourage plant growth. While these lights can provide a better spectrum than traditional ones, they often use more electricity and have a high heat output.

Improper or insufficient aquarium lighting causes fish stress, lessened activity and coloration, and poor growth and health in fish and invertebrates. The goal of fish tank lights is to replicate the natural conditions of light in natural habitats. Most aquarium fishes need up to 12 hours a day of the appropriate level of daylight, and it's up to you to give them normal days and nights as they don't have any other way to normalize behavioral cycles (like spawning or even feeding).

Aquarium light bulbs are different from ordinary light bulbs, which promote detrimental algae blooms and can lack the spectral range needed for aquarium health and visual enhancement. Aquarium light bulbs come in a range of types, spectra and intensities depending on what type of aquatic life you have and the depth of your tank