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A Guide To Choosing The Best Light Spectrum For Your Aquarium Plants

Freshwater aquarium fish
Freshwater aquarium fish

If you’re looking for the best light spectrum for your aquarium plants, consider using a light that has a blue-green colour. This type of light is perfect for plants that need lots of light but don’t need a lot of heat. Let us get into more detail:

What Is A Light Spectrum?

A light spectrum is a range of electromagnetic radiation visible to the human eye. It includes all the colours we can see in a rainbow, from red to violet and other colours that are not visible to us, such as ultraviolet and infrared light. The light spectrum is a continuous range of wavelengths, with each colour having a specific wavelength and frequency.

Different wavelengths of light produce the colours we see in the visible spectrum. Red light has the longest wavelength and lowest frequency, while violet light has the shortest and highest wavelength. Other colours, such as orange, yellow, green, and blue, have wavelengths and frequencies between these extremes.

The electromagnetic radiation not visible to the human eye is also part of the light spectrum. Ultraviolet light, for example, has a shorter wavelength and higher frequency than violet light. Infrared light, on the other hand, has a longer wavelength and lower frequency than red light.

Scientists use a spectroscope to separate the different colours of light and measure their wavelengths. By analysing the spectrum of light emitted or absorbed by a substance, scientists can determine its chemical composition and other properties.

Overall, the light spectrum is a fundamental concept in physics and has a wide range of practical applications in optics, astronomy, chemistry, and biology.

What Is The Best Light Spectrum For Aquarium Plants?

Blue Light

Source: Google

Blue light is considered the best light spectrum for aquarium plants because it plays a crucial role in photosynthesis. Photosynthesis is the process by which plants convert light energy into chemical energy, which they use to grow and thrive.

Blue light is essential for photosynthesis because it is absorbed by chlorophyll, the pigment that gives plants green colour. Chlorophyll absorbs light in the blue and red parts of the spectrum most efficiently, which is why aquarium lights that emit light in these spectrums are preferred for plant growth.

While red light is also important for photosynthesis, blue light is especially beneficial for aquarium plants. This is because blue light helps regulate plant growth and development, stimulates chlorophyll production, and enhances photosynthesis efficiency. Blue light also helps prevent algae growth, which can compete with aquarium plants for nutrients and resources.

Furthermore, blue light has a shorter wavelength than other light colours, which means it can penetrate deeper into the water and reach the lower parts of plants that may not receive as much light. This makes it especially important for aquariums with taller plants or deep tanks.

Red Light

Source: Google

While blue light is often considered the best light spectrum for aquarium plants, red light is also important and beneficial for plant growth. Here are some of the benefits of red light for aquarium plants:

  1. Promotes flowering and fruiting: Red light is particularly important for plants that produce flowers and fruits, as it stimulates the production of hormones necessary for these processes. Aquarium plants that require flowering or fruiting, such as certain species of Anubias and Cryptocoryne, can benefit from a red light.
  2. Enhances photosynthesis: While blue light is essential for photosynthesis, red light also plays a significant role. Red light is absorbed by the chlorophyll pigment in plants, which helps to drive photosynthesis and promote growth.
  3. Supports stem growth: Red light has been found to promote stem growth in plants, which is important for the overall health and stability of the plant. Plants exposed to red light tend to have thicker stems, which can help prevent them from falling over or becoming damaged.
  4. Reduces stress: Exposure to red light has been shown to reduce stress in plants, particularly in situations where the plants are experiencing low light or other environmental stressors. Red light can help to promote recovery and growth in plants that have been stressed or damaged.
  5. Can be combined with blue light: While blue light is often considered the best light spectrum for aquarium plants, red light can be combined with blue light to provide a complete spectrum of light. Aquarium hobbyists can provide a balanced and optimised light environment for their plants by using red and blue light.

White Light

Source: Google

White light is a combination of all the colours of the visible light spectrum, including blue and red light. While blue and red light is often considered the best light spectrum for aquarium plants, white light can also provide a range of advantages for plant growth and health. Here are some of the advantages of white light for aquarium plants:

  1. White light provides a full spectrum of light, including blue and red light, which can provide a more balanced and natural light environment for aquarium plants. This can help to promote healthy and balanced growth.
  2. Promotes photosynthesis: Blue and red light are the most important light spectrums, but white light can also stimulate photosynthesis and promote plant growth.
  3. Enhances plant colouration: White light can enhance the colouration of aquarium plants, particularly for plants with red or purple leaves. This can provide a more visually appealing and attractive display in the aquarium.
  4. Mimics natural sunlight: White light can help to mimic the natural sunlight that plants would receive in their natural environment, which can help to promote healthy growth and development.
  5. Versatile for different plant species: White light is versatile and can be used for a range of plant species, making it a good option for aquarium hobbyists with various plants in their aquariums.

Why Do Aquarium Plants Need Good Lighting?

Aquarium plants require good lighting to grow and thrive. Light is essential for plants because it is the energy source they use to carry out photosynthesis, which is the process by which they convert light energy into chemical energy to fuel their growth and development.

Good lighting provides the necessary energy for aquarium plants to:

  1. Produce oxygen: During photosynthesis, plants produce oxygen as a byproduct, essential for the aquarium’s fish and other aquatic creatures to breathe.
  2. Regulate carbon dioxide levels: Plants consume carbon dioxide during photosynthesis, which can help regulate carbon dioxide levels in the aquarium.
  3. Create nutrient synthesis: Plants require nutrients, such as nitrogen, phosphorus, and potassium, to grow and develop. Good lighting helps to promote the production of these nutrients in plants, which can help them to thrive.
  4. Promote healthy growth: Without adequate lighting, aquarium plants can become weak, stunted, or discoloured. Good lighting provides the necessary energy for plants to grow tall, develop healthy leaves, and produce flowers or fruits.
  5. Prevent algae growth: Algae can quickly grow in an aquarium with poor lighting conditions. Good lighting helps to prevent algae growth by promoting the healthy growth of plants, which can compete with algae for nutrients and resources.

It’s important to note that not all aquarium plants have the same lighting requirements. Depending on their species, size, and growth rate, some plants may require more or less light. Aquarium hobbyists should research the lighting requirements of their specific plant species to ensure that they are providing adequate lighting for optimal growth and health.


The best light spectrum for aquarium plants is a mixture of high and medium-intensity light. This will give the plants the stimulation they need to grow and thrive and let you see their growth.


Can aquarium plant life benefit from full-spectrum light?

Full-spectrum or daylight bulbs closely resemble the visual impact of natural sunshine since they emit all visible light wavelengths. They combine every hue found in the colour spectrum. All varieties of freshwater and saltwater aquariums are the best candidates for these all-purpose bulbs.

Which is better for aquarium plants: LED or fluorescent?

As long as the light intensity is sufficient, you may use practically any type or brand of light to grow plants. However, we strongly advise investing in an LED light instead of a fluorescent, compact fluorescent (CF) or another form of light technology.

What shade of lighting draws more fish?

Generally, the colour green draws the most fish. Green has a 520 nm wavelength and a high brightness output of 130 per LED. Shrimp and insects have green light receptors of approximately 530 um, both wavelengths in their colour vision.