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Lighting – Aquarium Lighting Options

There are many aquarium lighting options available to the home aquarist. In this video the focus is on the aquarium lighting options that are offered by the market to the marine reef aquarists.  Although this may seem to be a bit away from the needs of the freshwater tropical fish tank, it actually provides useful background on the way light is delivered underwater.  There are a number of actual light sources identified.  Actual illumination is not all from the direct input of the sun. has built up a large library of excellent videos informing people of the most current topics of interest to the reef aquarist. Much of the data and products they suggest are well beyond the needs of the home freshwater aquarium, but the principles and foundations they offer are quite relevant. That is especially true when discussing lighting, especially for the planted aquascapes that are becoming more and more popular.

Their discussion of lighting breaks the way natural light is delivered underwater into four basic types. All are important for a planted tank as well.

The Four Natural Lighting Options

The most obvious light is directly from the sun, this is a pinpoint illumination and Metal Halide or halogen style bulbs deliver light in this way. In the freshwater tank, this is a fixed point where the light can originate. It rarely causes problems for freshwater plants. But it is not diffuse and can leave areas in shadow where nothing can grow. In nature, clouds and storms diminish the power of the sun underwater. this is not the case for artificial lighting. Technology has created very strong light sources – they can overpower plants or corals and cause harm. It is not always the case where more is better

The second source is from the diffuse light delivered by the sky – light is reflected throughout our atmosphere and then is directed underwater from a wide area while the sun shines. In the aquarium, this type of lighting is quite popular and commonly delivered by a fluorescent fixture’s long tube(s). The light is more diffuse from above and lessens the chance of a place remaining too dark.  More of the aquarium is lit and able to provide enough light for plants to grow. This is the most common lighting.  The advent of T5 bulbs for the aquarist has kept this fixture popular for planted aquarium enthusiasts.

The third type of illumination of corals is the reflection of light from the substrate and aquascape elements. In a freshwater aquarium, this is not a major source.  However, it could an added light source important for reef tanks where the substrate can be much more reflective.

Finally the last part of lighting is termed shimmer. This refers to the pleasant light bursts that occur as the rays pass through the ripples and waves and deliver a shimmering effect to the underwater scene. It is quite pleasant, but much more important than many realize. The shimmer actually focuses and increases the light bursts much like a magnifying lens, offering irregular but powerful burst of light throughout the habitat.  One fo the new and upcoming aquarium lighting options is LED.  The use of many distinct points of light permits shimmer to be added.  The way the surface ripples will cause shimmer and in fact it is one of the prominent selling points for this style.  The multiple diodes also can be programmed independently to provide more natural light sources mimicking the passing of clouds and storms make it a very appealing light source for many reef and a growing number of freshwater plant aquariums.

When trying to artificially produce all of these sources into viable aquarium lighting options, a combination of lighting technology seems to be the way many solutions are being developed. By combining Metal Halide with programmable LED in various light spectrums most of the four light sources found in nature are being imported to the home aquarium.  Some of these aquarium lighting options are quite expensive, but knowing what to replicate makes a world of difference when trying to duplicate into the home environment.


Steve Pond, of Tropical Fish Aquarist, has kept fish both personally and professionally for over 50 years.  He writes regularly on the wide range of current topics that are important to people who keep tropical fish tanks as a passion and a hobby.

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About blueram

Steve Pond, of Tropical Fish Aquarist, has kept fish both personally and professionally for over 50 years.  He writes regularly on the wide range of current topics that are important to people who keep tropical fish tanks as a passion and a hobby.

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