About Aquarium Lighting

As you set up your new aquarium, one of the most important items you will add to it is the lighting. Do not assume that the lighting that came with your aquarium kit is sufficient. Lighting is much more than simply a decorative option for your tank. Fish and underwater plants need specific types of lighting to thrive, and failing to provide them with it will inhibit growth and create a stressful environment for your new pets.

  1. Function

    • Lighting is one of the ways an aquarium owner seeks to replicate the natural environment for pet fish. Fish need around 12 hours of light each day. Without enough light or with too much light, they will not experience normal days and nights. This will throw off behavioral cycles, such as breeding or feeding routines. Insufficient light will also decrease the fish's activity level and coloration. Overall, improper lighting creates stress for the fish, which can lead to disease and eventually premature death.

    Light Spectrum

    • The spectrum of the light you choose is important. The Kelvin scale (K) is used to measure spectrum. Natural sunlight is 5500K. Most freshwater fish and plants along with some shallow-water saltwater fish will thrive in aquariums with a Kelvin rating of between 5500 and 6500K. Reefs and deepwater saltwater fish need a light around 10,000K, which is a white light that gives off a bluish cast. You can also buy 20,000K lamps. These create an intense blue light and are ideal for very deep tanks or fish accustomed to very deep water.

    Actinic Light

    • Actinic light is an important light source for reef organisms as well as fish from deep waters. It is a low-intensity light that does not register on the Kelvin scale. These lights produce UV light from the blue end of the color spectrum, which will penetrate deeper into the water. This lighting is absorbed well by non-fish creatures in a saltwater aquarium, such as coral or invertebrates. Many light fixtures designed for saltwater aquariums have actinic lighting combined with traditional bulbs to provide the benefit of actinic lighting along with the brightness of traditional bulbs.

    Lunar LED Lighting

    • Lunar LED lighting is a low-intensity light that is designed to mimic the light from the moon. Fish breeders who are trying to establish a complete day/night cycle in order to encourage spawning will often use these bulbs. This light does not provide much illumination, but is used to create a more natural environment for the fish. Lunar LED lighting is available in blue or white. The white light is designed to simulate the light from a full moon.

    Types of Bulbs

    • As long as the Kelvin rating of the lighting you choose is correct, the type of bulb is not as important, but you do have a few choices to consider. Incandescent bulbs are screw-in bulbs similar to those used in home lamps. These are the cheapest, but they provide only around 2700K, which is not an ideal Kelvin measure. Because they are lower-intensity, these lights promote algae growth. Fluorescent lighting is another common low-cost option, and it is available with the right Kelvin ratings. Many reef aquariums now are lit with compact fluorescent bulbs, which are more energy-efficient.