Have you ever wondered why the image of the Earth’s Ocean taken from space appears blue? Certainly, this question will give an idea of why we might want to add blue light to the aquarium.

More or less, we are on the right track from a natural point of view, or maybe fishes can see adequately in blue light! Let’s find out.

There are many reasons why blue light for a fish tank is ideal for marine pets. We shall look at some scientific facts along with a logical explanation of this common yet less talk about ‘Blue Lighting’ used in most Aquarium worldwide today.

But, Can Fish See Blue Light?

Yes, I’m sure they can! For a starter, let’s go with the basic understanding of light comprising seven fundamental pigments abbreviated as VIBGYOR-


Fun Fact: All the other colors except VIBGYOR are formed by the combination of two or more fundamental colors. For example, Blue + Green makes Cyan

If B for Blue is visually recognizable as color, they must be seen by the fishes unless they are color blind like some men and women folks do.

What Does Blue Light for Fish in a Tank Do, besides Giving Visibility?

Various studies are conducted to ascertain the benefits of using blue light for Fish under confinement (tanks/aquariums). Several positive aspects derived from it include:

  • Stress Reliever
See also  Dead Fish in the Tank? Guide to Disposing, Cleaning, and More

Blue Light can come to the rescue as they are known to reduce confinement-induced cortisol (stress hormone) physiologically.

  • Relaxing Ambient Environment

Both freshwater and saltwater fish, specifically at the Juvenile stage in the aquarium, show calmness under the influence of blue light.

  • Reproduction

For a hardcore fish breeder, this information is undeniably going to be the norm, as studies have indicated that the presence of blue light can increase the mating frequency and intensity of adult fishes.

  • Improved Adaptability

Aquatic fauna is known to develop maximum adaptation in the dim light-a characteristic of blue, whereas red is the most depressing color. Indeed, another good reason to go blue for Marines.

  • Aesthetic Factor

Keeping an aquarium provides for the display of wide arrays of horizontal and vertical biodiversities representing rich fauna and flora.

Blue lighting can add more luminescence to such an environment.

Is Blue Light Good for Aquarium Plants?

Blue light can act as the balance between Good and Evil for aquatic plants varieties. According to data collected by NASA’s satellite-based remote sensing, blue areas of the earth indicate limited phytoplankton.

This translates to ‘blue spectrum presence in water bodies, which can arrest the excess growth of lower plant species,’ i.e., Harmful Algal Blooms– a potent source of toxic compounds to most aquatic animals and fishes.

Meanwhile, the higher species of marine plants and fishes can survive decently under blue lighting.

Authors Note: Higher-order species of flora and fauna have better adaptability than Lower-order species under similar environmental parameters.

Should We Use Blue LED in Fish Tank Lighting?

Affirmatively Yes! Blue LED lights have tonnes of advantages over apparently negligible drawbacks, i.e., the initial cost factor. However, it’s not like a Blue LED is 100 times more expensive, so let’s stick with LED first.

Benefits of Blue LED


In addition to saving watts on your electricity meter, one can be truly delighted to be a part of the Environment Conservation Movement.

See also  Nitrogen Cycle for Aquariums: How to Do It With Fish and Without Fish?

Photobiological Safety

A blue LED-lighted fish tank is considered the safest among other lighting devices. They do not produce infrared emissions and emit a negligibly low level of Ultra-Violet Radiation.

Easily Customizable

Blue LED lights are available in different types of shapes-Bulbs, Tubes, and Wires to suit the dimensions of your tanks.

Better Illumination

Blue LED has the highest optical delivery efficiency among other lighting systems available commercially- incandescent, fluorescent, etc.

Your aquarium pets may even glow if they are bioluminescent towards blue pigment, and one may expect most marine organisms to be one!

Quick Fact: Bioluminescence is the phenomenon exhibited by living organisms especially aquatic species to glow in dim/darkness.


Blue LED lighting can last from 30000 hours to 100000 hours which is extraordinary over other alternatives offering less than 50 percent longevity in comparison he LEDs.

Cold Temperature Operations

They show excellent performance in low-temperature conditions. Another argument to consider is why blue LED lighting can be best suited for an aquarium purpose.

Is Blue Light Good for Fish at Night?

Currently, there is no significant research to substantiate the benefits or harm of using Blue light on a fish tank at night, but that does not mean it can roadblock a marine enthusiast’s curiosity.

Most fish breeders use it often without any observable negative consequences. To put it into an analytical perspective, Blue light is the ideal balance between night and day, so their role should be neutral.

Overall, my honest opinion would be to follow the Law of Nature, i.e., 8-12 hours of darkness sounds better.

Which is Better, White or Blue Light for the Aquarium?

Blue light would be the better alternative, and blue has the optimal penetration power through water in addition to the benefits discussed earlier.

There is no doubt that white light contains a spectrum of shades to produce a different kind of illumination on a surface, but not always.

See also  Can Fish Drown in Water? - Busting the Myth of Fish Drowning

Interesting facts: Light behave differently from one medium to another. In this context, the illumination power of white light (Polychromatic) may change in water (denser medium) whereas Blue light is a monochromatic source of higher energy and stability.

With white light usage, other types of unwanted organisms- Phytoplanktons and microorganisms may coincide and compete for oxygen and nutrients with the fishes.

Accumulation of more waste products – carbon dioxide, Ammonia, Nitrates, etc. can be expected.

Despite all these, using white light will make you occupied with responsibilities in the following ways-

  • Timings

One would have to switch off/on the light source regularly to compensate for the diurnal and nocturnal habits of inhabitants.

  • Cleaning

Regular intervals of removing unwanted by-products from the tanks

  • Frequent Replacements

Tank components like air and water filters.

  • Additional oxygen pump for each tank

The oxygen level in your tank will get used up quickly because of the higher number of organisms growing along with the intended inhabitants.

Can Fish Sleep with a Blue Light On?

Yes, they can, although it is not recommended. If you want to opt for keeping the blue light on overnight, it would be reasonable to dim the light at least. For such purposes, an adjustable light intensity regulator can be used efficiently.

Key Takeaways

There is no better alternative to choosing blue light over other colors when it comes to Fish Tank lighting. It is smart, versatile, and would not disappoint you.

Using LED instead of alternative conventional lighting will further enhance the Power of Blue Light in your Aquarium.

As we all know, the highest density of species occurs in the marine habitat. We believe your aquarium is a mini version of such Beauty in Nature that you objectively or subconsciously seeks to promote within your private space.

Let’s add more exhibitions to our aquarium with Blue Lighting!

About the Author

Dr. Vituotsolie Kiso

Vituo Kiso is a budding Veterinarian and marine species enthusiast. He did most of his internships in several Pet Clinics, Wildlife centers, and Farms across India. He has a passion for learning new things and writings besides giving consultations and treating pets. Career Highlights: Almost 3 years of experience as a Veterinary Practitioner Online Pet…

View All Articles