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Aquarium Light Guide

Updated on April 13, 2010

Nothing is more important to the health of fish and plants in an artificial ecosystem than an aquarium light.  The right aquarium lighting will encourage plant growth, which will help with the oxygenation and filtration of water and improve the energy levels and colors of the fish that live in it.  Aquarium lights are not universal.  Though there is a light for every situation, not every light can be used in any situation.  Even with the most careful monitoring of water quality and a meticulous cleaning schedule, fish and plants cannot survive without the right lighting conditions.  Conversely, the right light can restrict the growth of algae, which will simplify the cleaning process and help keep water quality constant.  If you are hoping to start a new aquarium, or have not seen the results you expected with your existing one, a new aquarium light may provide the solution you have been looking for. 

Standard lighting with fluorescent light bulbs.
Standard lighting with fluorescent light bulbs.

A good aquarium light bulb is designed to closely mimic the conditions found in the natural habitat of fish and plant life. Tropical fish tanks should be placed in an area that is shielded from natural light, with only the lighting system that has been installed for illumination. It is important to carefully control both the amount of sunlight to which a tank is exposed, as well as the tank’s temperature. Only artificial light will guarantee the correct intensity and depth of penetration. Exposure to natural sunlight will result in uncontrolled algae growth, wild fluctuations in temperature, and an irregular daylight schedule.

Aquarium light bulbs are differentiated by spectrum and intensity. Light spectrum is measured in degrees Kelvin and refers to the temperature and color of light. Sunlight in the air is typically measured at around 5,500 K, but this measurement will change when sunlight is refracted in water. The K measurement will change depending on depth, rising as water gets deeper. Make sure that the K rating corresponds to the appearance of sunlight at a fish’s natural depth.

Light intensity is measured in watts, and is a measurement of the light’s power and penetration. Larger tanks and those that are supporting both plant and animal life will require higher wattage bulbs. Wattage is directly correlated to the amount of energy required to power the bulb, so high wattage lighting may have a noticeable impact on energy bulbs.

This aquarium is lit with lunar LED lights.
This aquarium is lit with lunar LED lights.

To reduce the cost of running aquarium lighting for 12 hours a day, consider aquarium LED lighting. LED (light emitting diode) lights are typically more expensive than fluorescent or filament bulbs, but they require far less energy to run, and will burn for many more hours before requiring replacement. For situations requiring high intensity light, LED lights are favored because they produce little heat, and will not affect the ambient temperature of the water. This will save the expense of an external cooling system, and make controlling the conditions in a fish tank far easier. LED lighting has been a popular choice for years, and the bulbs will fit into most standard fixtures and can be purchased from almost every major pet store.

This fish tank is lit with three metal halide aquarium lights.
This fish tank is lit with three metal halide aquarium lights.

Metal halide aquarium lighting is the newest lighting option on the market.  For anyone who is looking for effective, saltwater reef aquarium lighting, this is by far the best option.  Reef tanks require up to four times more wattage per gallon as fish only tanks, and metal halide aquarium lights can provide this intensity with a single bulb.  Their high intensity makes them expensive to run, and be aware that they do produce a lot of heat.  Most DIY metal halide lighting kits will include fixtures, ballasts and a cooling system to help keep temperature constant.  For reef tanks, which must be kept at a near constant 80° F, lights should be installed at a time when owners will be available to closely monitor tank conditions. 

         Many dedicated aquarists believe that in addition to simulating daytime light conditions, a second light source should be installed to replicate moonlight.  Most experts agree that keeping on a soft light with a low intensity for the remaining 12 hours in a 24-hour day will help fish maintain their normal life cycles.  Lunar LED night lights are popular choices, both for their low energy consumption and the aesthetically pleasing way they illuminate a tank.  Program a lighting timer to regulate the switch from artificial day to night to provide consistency and reduce the amount of stress on the fish.

         Finding the right aquarium light for any tank is easy with some research and expert guidance.  When purchasing your fish, ask about the manner in which in-store tanks are lit for a place to start. 


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    • profile image

      Topline LED aquariumlight 5 years ago

      The new design of 2012 -Full spectrum Led aquarium light with UV ,Red colors added for a better coral growing,the intelligent controller equipped as well to simulate sunrise sunset moonlight vision.More important is 3 years warranty,CE ROHS passed with BEST PRICE.

      Just let's talk email: bztopline06@hotmail I'm Gary

    • profile image

      Light up Aquarium 6 years ago

      Hello guys,

      anyone who need les aquarium light information just email to , i will be always at your service

    • profile image

      greensun 6 years ago

      Dear Sir/Madam,

      Hereby I introduce ourselves – Hong Kong Green Sun Industrial Co.,Ltd., as a professional LED light manufacturer. We are located in Shenzhen which is the biggest seaport and airport in China.

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      Hong Kong Green Sun Industrial Co.,Ltd.

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    • profile image

      Light up Aquarium 6 years ago

      Hello, everyone , what make you hesitate to buy led aquarium light for your aquarium is that the price is a little unacceptable, it is because most of the customers buy the lights from the destributor or trading company , which rise up the cost of the lights.

      why not buy form the factory directly? we are the TOP3 led aquarium light manufacturer in China , Any different models with ranging outputs as well as some customizations of the color ratio are available for us, you can save a lot of money and got the most suitable light for your fish,coral &reef

      please visit our site for more information

    • profile image

      Vince 7 years ago

      This one is very informative. So, just a question, where they able to invent now a light that has the light intensity of the moon?

      What light is it?

    • alex.chen profile image

      alex.chen 7 years ago

      Nice Hub! Just a quick question about LED lighting...

      I have a nano-reef starting (10 gallons). I have experience in salt water aquariums before, but never have I used an LED light for my saltwater lighting. I have read that some are not powerful enough for saltwater lighting, and I have also read the contrary. Could you please clarify this for me? Thanks!

    • infoguider profile image

      infoguider 7 years ago

      Yeah, I absolutely agree. It gives the entire room a soothing ambiance and adds a lot to the décor in general.

    • ConradM profile image

      ConradM 8 years ago from San Francisco, CA

      Not only is lighting great and essential for many inhabitants, but it also just makes everything look better. I have a saltwater reef at home and it really looks great when the blue actinic lighting comes on in the morning and evening.