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The Complete Fish Tank Lighting Guide

A complete guide for all your fish tank lighting needs, Choose the best lighting and what kind of lighting your need in your home aquarium with our full and complete aquarium lighting guide.

The Complete Fish Tank Lighting Guide

Introduction to Fish Tank Lighting.

First-phase aquarium buffs think lighting is necessary to warm the water when that’s not the true function of an aquarium lighting system. You should leave that job to your heater. Most newbies also think that it’s necessary for their fish. Aquarium lighting might be necessary for coral and plants, but it is not for the fish. So, you need to think in terms of the tank size and the environment you are building.

Tanks with plant-life require lighting to promote photosynthesis, and tanks hosting coral require yet another lighting set-up. Since light is a source of color, you have to think about the tank placement, depth, and composition.


Each aquarium lighting has its own strengths and limitations. Finding out what they are is essential in picking the right one for your tank. Continue reading this guide to find out more on each of the aquarium lighting options above or click on the links above to jump to it’s category.


T5 Aquarium Lighting

The T-5 fluorescent is tubular and 5/8-inch in diameter. What’s great about the T-5 is that it is inexpensive, produces low heat, and grows most corals well. On the downside, a T-5 needs to be replaced at least once a year, does not project into deep tanks, cannot be dimmed, and requires some voltage.

A T-5 fluorescent emits 65 lumens, a measure of the visible light. It is compact and approximates the golden rule of 3 watts per gallon. And, it produces the light necessary to reach 20-inches in depth.

A Beautiful Reef Tank With T5 Aquarium Lights – by Masterbuilder (source)

A T- 5, unfortunately, uses a HO light ballast that can be a problem. Because of this, at least one expert recommends sticking with “the standard output versions.” Nonetheless, technology is moving fast enough to leave the T-5 well in the past.

The T5HO (High Output) has a higher lumen output but generates less heat than the VHO (Very High Output). The T5HO is also more energy-efficient and lasts up to three years.

Other Fluorescent Aquarium Lighting

The aquarium lighting in most starter tanks is simple fluorescent lighting.It is enough to make the tank look natural and the fish colorful. If you stick with the usually recommended 3 watts/gallon, you will manage the algae and show off the fish. Fish-only tanks only require normal output fluorescent lighting (NO).

Fluorescent bulbs come in a number of lengths, from 18 to 72-inches, and as the bulb gets longer, it produces more watts. A typical fluorescent is four to six times as energy-efficient as a conventional incandescent lamp because it puts its invisible ultra-violet light to work.

A T-12 fluorescent is the widest bulb at 1.5-inches, the kind usually found in a shop light. They are cheap and easily available. And, some vendors sell them with aquariums. But, in terms of their ability to produce lumens per watt, they are energy inefficient.

A T-8 runs about 1-inch in width, and will use 32 watts at 48-inches in contrast to the T-12’s 40 watts. Because of the slightly higher efficiency and the size, the T-8 is the aquarium lighting of choice for new collectors.

A T-2 measures a mere 0.276-inches in diameter, so a number of 13 watt 20 inch bulbs can light your tank. Each T-2 will produce 950 lumens, and their size makes them perfect for small-to-medium planted environments (less than 18-inches deep). And, the bulbs link together for larger tanks.

The T-2 fluorescent needs fewer watts to produce the light energy needed by plants and coral, so they are often used to complements LED lights. Some complain about the lack of size selection, and there is some evidence of faults in the soldering and the ballast required to regulate electrical current through the fluorescent tube. But, quality control seems to be managing these problems as the product has been on the market longer.

VHOs (Very High Output) send more current to the bulb – some of them at 40-inches. It can produce twice the lumens as a conventional fluorescent. The VHO burns twice as hot and degrades faster, so they need to be changed three times a year – especially if you notice algae forming or coral shutting down. It would appear the VHO comes with the penalty of frequent bulb and ballast replacement.

The CFL (Compact Fluorescent Lamp) have the same efficiency as the T-5, but they come in straight pin and square pin arrangements. They also comes as a screw-in like an incandescent fixture. Popular and economical, they are the choice for planted freshwater worlds.

The SHO (Super High Output) is a new power compact for planted and reef aquariums as well as hydroponics – because of their full spectrum light output. These lamps work in conjunction with reflectors to maximize the efficiency. The bulbs go for £20 each, and the installation is a do-it-yourself project. But, the health of the fish, plants, and coral make it worth the cost and trouble.

Metal Halide (MH) Aquarium Lighting

Because of its unique depth penetration, full light spectrum, and output, the Metal Halide is set as the lamp-of-choice for reef aquariums. They have been the favorite because of their markedly favorable effect on coral and effectiveness in hydroponic nurseries.


For tanks 30 or more inches deep, the MH has been tough to beat. It is an arc light, a sort of miniature version of the mercury vapor lights on highways. They produce a bright white light with energy efficiency.

The MH is sold with a Mogul base or a High Quartz Iodide (HQI) which is double-ended.

The Mogul screws in and comes in a selection of color spectrum and wattage, and they look like an “old school” radio vacuum tube. The double-ended will last longer than the screw-in.

The HQI have a cleaner color spectrum, produce less heat, and last longer than the screw-in. But, because of the heat generated by either configuration, you need a hood fan.

LED (Light-Emitting Diode) Aquarium Lighting

LED Aquarium Lights

LED Aquarium Light Effects (source: Eric Danley – Flickr)

Aquarium lighting has a new best friend in the LED with its semiconductor technology.

The LED projects no heat into the water even if hung directly above the water. They last up to 50,000 hours and can be mounted easily.

LEDs produce less yellow/green light making them look less bright. Instead, they emit light in one specific direction, so you can rotate the tube to redirect the light effectively. This virtue makes them more energy efficient because the lumens are not wasted.

Because of the semiconductor technology, the complex system of emitters and circuitry, the LED remains high-priced.

Aquarium lighting is necessary to stimulate the growth of plants and aid the digestion, feeding, and reproduction among the fish. So, your choice in lighting – heat, lumens, color spectra – all affect the health of your aquarium environment.

Here's a useful video on fish tank lighting for your home aquarium.


What’s Your Favorite Aquarium Lighting Setup?

Share your favorite aquarium lighting setups with other aquarists like you in the comments section below. Fish Tank Keepers.

Equipment Fish Tank lighting

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