Aquarium lighting is the heart of any planted aquarium. It powers the photosynthesis of plants and at the same time provides beautiful color tones for both plants and fish.

LED aquarium lighting technology has evolved significantly over the past 10 years. Modern LED lights are more energy efficient and more powerful than older systems, such as T5 fluorescent tubes. In addition, many LED lighting systems improve the visual presentation of colors in the aquarium.

Today's lighting systems offer a range of features, from spectrum adjustment to built-in timers. Some models also have more fancy features, such as simulated lightning or "disco effects." However, these extras are often more for show than for real benefit.

For new aquarists, choosing the right lighting can be confusing. In this article, we will look at the main aspects to consider when choosing lighting for your planted aquarium.

How to Light Your Aquarium: Rim or Suspended


Lights can be suspended and hung from the ceiling or stand for a cleaner, sleeker look in rimless tanks, or mounted on the rim of the aquarium itself.
If the lighting is placed a long way from the water, the light level in the aquarium is significantly reduced. However, special pendant LED lights are designed with this in mind and are usually more powerful to compensate for the loss of intensity.

Installing pendant lights requires a little more effort, but gives you more free space above the aquarium. This allows for a great view of the fish and plants, as well as easy access for maintenance and cleaning the aquarium.


Pendant lamps attached to the ceiling: Week aqua a430.


Висящата лампа LEDSTAR AQ-X предлага лесен достъп до аквариума и страхотна гледка отгоре

So, what really matters? 3 important factors for evaluating LED lighting


Factor 1: Wattage - measured in μmol PAR


PHAR (Photosynthetically Active Radiation) is the most accurate measure of the “power” of light as it relates to plant growth, as it directly measures the amount of light available for plant photosynthesis. It counts all photons in the 400 to 700 nanometer range that plants use for photosynthesis.

Most reputable manufacturers provide PAR data for their lights in the form of PAR charts. Additionally, hobbyists with PAR meters also share measurements that you may find helpful.

But what if there are no PAR charts or data from other hobbyists available? One way is to look at aquariums lit with the specific lamp. If other aquarists are successfully growing the same plants that you want, there is a good chance that the lamp will work for your aquarium as well.

Today’s powerful LED fixtures also allow for adjustable light output, making controlling plant growth even easier.

Read the blog post for more information, “How to Read Manufacturers’ PAR Charts.”

Moving a PAR meter around the aquarium will show that PAR levels at the top of the aquarium, near the light fixture, can be many times higher than the light levels reaching the substrate level. The rate at which PAR drops with aquarium depth depends on several factors and is often not completely linear. This is because glass walls reflect light internally, and different fixtures can produce more focused or diffused light, which affects how effectively light penetrates the water.

Also read the article "What Part of the Light Spectrum is Used for Photosynthesis?" for information on what part of the light spectrum powers photosynthesis.

How Much PAR Should an Aquarium Have?

When people say they use 100 micromole PAR in their aquarium, this is usually an average measurement taken at the substrate level of the aquarium. The general guidelines commonly used by the aquatic plant community are as follows:

PAR Стойности

Suitable for

20 до 40 μmol Low light levels - suitable for shady aquarium plants such as Anubias, Java fern, Cryptocoryne and mosses. The light levels are so low that they easily cope with algae.
40 до 90 μmol Medium Light Levels - With good CO2 levels you can grow most common aquarium plants and good colors for red plants at the higher end of the range. Suitable for Iwagumi and natural style aquascaping. Carpet plants grow at a good rate at this light level.
90 до 150 μmol High Light Levels - Great for highlighting the coloration of red/non-green aquarium plants and cultivating demanding species. High light levels provide greater plant density and growth rate. However, this level of lighting requires good control of aquarium cleanliness and plant health to avoid algae problems.
150 μmol +Very high light levels - Sunscreen effect on red/non-green plants to achieve the most intense color tones. Allows for even greater plant density and tightly packed bushes. Requires expert maintenance to keep the aquarium algae-free.


Contrary to popular belief, carpet plants such as Dwarf hair do not need a lot of light to grow well. For Iwagumi aquascapes it is better to use lower to medium light levels - this minimizes algae.


Higher light levels give an advantage in propagating difficult to grow species and give great color and density to the flower plants. Rotala florida and Eriocaulon quinguangulare are two fussy, light-demanding species. Grown here at 300~ μmol PAR at substrate level from a Week aqua a430 aquarium lighting.

What are lumens?

Some outdated websites quote lumens, but they are a poor unit of measurement because they measure the brightness of the light relative to the sensitivity of the human eye. This means that lights with a high green wavelength have a higher lumen rating because the human eye is more sensitive to green than to red or blue. However, plants use red and blue light efficiently for photosynthesis, so strong red/blue lighting may have low lumen values, but can be really great for growing plants.

The Superpower Lamp Trend

Do you need 167 micromoles PAR to grow Anubias and Java ferns in a low-tech aquarium? Probably not, and too much light exacerbates algae problems.

Due to competition in the industry, aquarium lights are becoming more and more powerful over time. More expensive models from popular brands such as Week aqua, Netlea, Chihiros produce an enormous amount of light for their size. Using much more light than is necessary to achieve the goals of the aquarium is the downfall of many inexperienced aquarists.

Most carpet and common plants can grow even at 40 μmol PAR, as long as CO2 levels are sufficient. Most high-power LED fixtures have controllers that allow for a reduction in the power level - aquarists should start their planted aquariums with lower light levels and adjust them up as their tanks develop.