What Size LED Lights Do I Need for My Aquarium?

You might need different light colors for aquarium plants.
i Grégory DUBUS/iStock/Getty Images

Let your fish strut their stuff in style by providing the right amount of light for your aquarium. When you've decided on LEDs as the type of lights you want, get the right size to help replicate the fish's natural environment in your home aquarium.

LEDs vs. Other Lights

With a variety of light choices, there's one to meet nearly every need. LEDs provide energy-efficient light while giving off less heat than other types of bulbs such as incandescent or fluorescent. Because LEDs use light-emitting diodes rather than bulbs, they typically last longer than other options. They also give you flexibility in the layout that you might not find with other lighting choices. For example, the LEDs might cover the entire length of the tank top, or they could clump together to spotlight certain areas of your tank.

What About Watts?

The light should make your fish feel at home; too much or too little can disrupt their normal sleep and eat cycles. The watts, or the amount of energy used to produce light, should reflect the depth of your tank to make sure the entire aquarium receives even lighting. In general, use the equivalent of 175 watts for shorter tanks, such as those less than 22 inches deep. For tanks 22 to 28 inches deep, pick 250-watt options. For deeper tanks, use more powerful lights, such as 400 watts.

Sizing the Lights

When it comes to lighting your tank, size matters. Most fish tanks need 1 to 3 watts per gallon of water, while those with plants need 2 to 5 watts per gallon. LEDs work differently than traditional lighting options because they're more energy efficient. They often come in 1- and 3-watt options; the more LEDs you use, the higher the overall wattage they produce. For a small tank, 18 1-watt LEDs on a 12-inch heatsink fixture should equate to 175 watts. If there are 24 LEDs on the same fixture, you have 250 watts of light, and 36 LEDs gives you 400 watts. The same number of LEDS on a larger fixture lowers the wattage; for example, 36 LEDs on an 18-inch heatsink bar is equivalent to 250 watts. When purchasing LEDs, read the manufacturer's specifications to determine how many watts the fixture provides.

Day and Night

Fish might not close their eyes, but they do need their beauty sleep. The most successful aquariums mimic the fish's natural environment as closely as possible, and that includes giving them some down time. Many LED kits include lights to illuminate your tank at night, often in shades of blue. When you turn off the bright daytime lights, the softer night lights allow you to enjoy your tank without interfering with the fish's sleep schedule. In LED kits containing both light types, there are usually fewer blue lights than white; for 18 white lights, for example, the kit might have three blue ones. Many kits offer timer options so you don't have to remember to turn off the white lights every evening.

the nest