What Color Light Stops Fish Tank Algae Growth?

Algae make their food through photosynthesis, a light-driven process. Thus, the lighting conditions in your fish tank may promote or inhibit algal growth.”

There is no specific color of light that stops fish tank algae growth. Specific light colors like blue, red, or white may promote the growth of certain algae species, but it depends on the algae’s pigments. Adjusting light intensity may be more effective.”

Various studies have investigated the effects of light color, intensity, and wavelength on algae growth. Learn more about them in the rest of this article.”

How Does Light Color Affect Algae Growth?

Photosynthesis is necessary for plant life, including algae. Pigments in the plant, such as chlorophyll, help capture energy from light to use for photosynthesis.”

Light color affects algae growth through the pigments present in the algae. Different species contain different kinds of pigments. However, these pigments absorb only specific light wavelengths. Some absorb blue light better, while others absorb red or green wavelengths most effectively.”

There are many kinds of pigments present in plants and algae. Some popular pigments are chlorophyll a and b, which prefer blue and red light colors. Chlorophyll causes algae to appear green (e.g., green algae).”

Other pigments in algae help them absorb different colors besides red and blue. Phycobilins and carotenoids allow some algae to absorb green color light.”

Red algae have phycobilins, specifically phycoerythrin. Certain algae may also have carotenoids, which makes other plants (like carrots) have a yellow to orange color. Another pigment is chlorophyll ides, present in chromophyte algae.”

With all that information, you may look into the kind of algae prominent in your fish and tank and see what pigments they have.”

If their pigments are good at absorbing blue and red colors only, you can test if avoiding those light colors in your tank would inhibit their growth.”

What Color Light Promotes Algae Growth?

As you might have guessed already, the color of light that promotes algae growth depends on the algae present and its pigments. However, there may be general colors that lead to their proliferation.”

Blue, red, or white color lights may promote algae growth, according to some recent studies. However, this depends mainly on the type of algae present. Algae with other pigments besides chlorophyll may be able to thrive in colors besides blue or red.”

In a study entitled “Red, White, or Blue: Which color is right for you? Algae Growth under Different Colors of Light,” the researchers determined that their algae samples grew the most under white and blue light and least under red light.””

On the other hand, the study “Impact of light color on photobioreactor productivity” discovered that a microalgae species grew best under white and yellow light. It grew least under the following light colors:

  • Deep red
  • Orange-red
  • Blue light

However, a combination of blue and yellow color lights helped improve algae productivity.”

Meanwhile, a study, “Enhanced algae growth in both phototrophic and mixotrophic culture under blue light,” found that the researchers’ algae species developed best under blue light conditions. It was also discovered that the algae preferred white light next to blue.”

You may be curious as to why, so far, white light is a favorite among algae. White light is a broad spectrum. In other words, it contains all the wavelengths of colors in the visible light range—it is a combination of colors. Thus, it appeals to a variety of spectra.”

Other Methods to Stop Algae Growth in Fish Tanks

Relying on light colors to stop algae growth in fish tanks isn’t the most efficient or optimal method. It’s reliant on several factors like the algae present, light intensity, and color pigments.”

Here are other ways to stop algae growth in a fish tank: 

  • Clean the tank regularly. Poor water quality, pollution, and waste promote algae survival in aquariums. Cleaning your tank and changing the water could help avoid these conditions and stop algae growth.”
  • Stop overfeeding. Providing your fish with excess food does not just lead to overfeeding. The leftovers can be converted into nitrogen compounds that help algae multiply.”
  • Adjust the lighting. Too dim and too bright lights can lead to algae growth. Adjust the lights regularly to optimal conditions. Usually, algae prefer bright lights.
  • Install a proper filtration system. Filters help keep your tank clean. However, if they aren’t working correctly, they can lead to a dirty tank in which algae will thrive.”
  • Cool temperatures. Algae multiply best in warm conditions. Get a thermometer and monitor the tank to help it stay at cool temperatures.
  • Install a pump. Circulation helps prevent dirt and debris from settling. Without debris or dirt, algae are unlikely to grow.
  • Opt for live plants. Live plants will compete and usually win over algae for nutrients. Without sufficient nutrients, algae cannot grow. Additionally, live plants offer many benefits.”

Final Thoughts”

The color and intensity of light affect the growth of algae. They may either promote or inhibit algal multiplication. However, relying on light conditions to control algae growth is often inefficient and difficult because of the many factors to consider. 


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