Can Fish See Blue Light? The Ultimate Answer

The idea of replacing the lights may have entered your mind if you’re thinking about improving an aquarium or just want to remodel the existing one.

Utilizing blue light is among many choices for illuminating your tank. Can fish see blue light? Is blue light good for fish?

Let’s dig into this post to get in-depth explanations!

Can Fish See Blue Light?

Fish tend to change their behaviors when you turn on the blue light in the aquarium. It means these aquatic creatures can see this lighting.

How does this lighting work in an aquarium? Your tank’s entire color scheme is blue due to this illumination.

Moreover, this lighting source also comes with other benefits. It allows you to observe your pets at night.

Besides, this illumination promotes healthy fish growth in the aquarium.

For example, most aquatic creatures feel comfortable in the relatively deep blue aquarium lighting.

Keep in mind that the spotlight is just on LEDs in this instance, namely LEDs that are a relatively deep blue.

That’s because these lights can generate blue light while generating only a little heat.

On the other hand, the incandescent variety of blue aquarium light bulbs appears to emit more radiation than light.

When using these bulbs in incandescent tanks, it is impossible to detect if your pets respond to illumination or heat.

Therefore, if you plan to set up this illumination for your aquarium, it’s better to keep these things in mind.

Blue lighting aquarium

Is Blue Light Harmful For Your Fish?

The answer is no. If you use this lighting properly, your fish can benefit from it. Here are some reasons.

These lights resemble the moonlight, and you may use them to make a switchover from morning to night and from sunrise to nightfall.

The objective is often to maintain illumination for one or two hours to denote the change from daylight to darkness and vice-versa.

Illumination is essential to fish. These creatures can establish a pattern and recognize a day/night habit thanks to light.

These aquatic creatures cannot tell the difference between day and night in a tank. Placing aquariums next to windows might help you solve this problem.

However, it is risky since the aquarium is directly exposed to sunlight, which can lead to sudden temperature fluctuations.

Your pets will require aquarium lights to establish a day/night routine if your aquarium is blocked from the sunlight, which will control their feeding and mating behaviors.

In terms of sleep, illumination is much more crucial. This species doesn’t have eyelids, so they can’t close their eyes to escape bright illumination.

For this reason, experts recommend aquarists establish and maintain regular day/night cycles in their aquariums.

Every night, fish need darkness for around 8 to 12 hours to sleep correctly. If not, they will battle crippling and maybe lethal stress.

blue fish in aquarium

Don’t leave the blue lights overnight.

Are LED Lights Harmful For Your Fish?

Do LED lights hurt fish eyes? Regular LED lighting for aquariums is safe and won’t harm your pets.

Depending on the breed and the placement of your aquarium, you may select how much LED illumination your pets will require.

You might not require LED lights with adequate indoor illumination or indirect sunshine. The minimum illumination quantity for your tank is 8 to 12 hours.

If you forget, using a timer to turn out the illumination system at night automatically is the simplest method to accomplish this.

Many aquarists opt for these lights because they guarantee safety by testing extensively to demonstrate that they will not harm your pets and other confined animals.

Before you install LED lights for your aquarium, consider the pros and cons:


  • Low heat
  • Longer lifespan
  • Several color choices
  • Reduction in energy use
  • Widespread illumination
  • Adjustable illumination intensity


  • Unfixed costs
  • Lack of accessibility
  • Too little illumination for several kinds of plants

led light reef tank

LED light won’t harm your pets

What Color Light Should You Equip Your Tank with?

What color light do fish prefer? Check the following recommendations:


Aquarium plants benefit significantly from this lighting. Since this color has a relaxing effect on these aquatic creatures, they are also fantastic for your pets.

This option enables the slower fish to rest peacefully and offers enough brightness for the more energetic species to continue swimming freely if your tank has both species.

These illumination aids bring out the color of red, blue, and green fish. It highlights the hues of the aquatic plants, particularly the red ones.

If you use a moonlight blue bulb, you can keep it on during nighttime.


This color may be more effective for keeping nocturnal fish to ensure that they may travel outside at night time without feeling overwhelmed.

Because they are somewhat warmer and relatively dull, bottom-dwelling creatures are more at ease stepping out of hiding places and moving freely despite this light.

The species like plecos or catfish will react more favorably to this color if you have them in your aquarium.

They’re additionally fantastic for plants since they are encouraged to grow taller and produce more blossoms.

It’s crucial to remember that if you use red lights, you cannot leave them on continuously as they may encourage algae growth.

That’s because algae require more frequency of red illumination for growth.

As a result, you will need to closely check its development in your tank when using this color option and turn it on less frequently.


Bluefish respond well to white lighting. It is perhaps the most popular light hue and comes in various choices.

White lights, on the other hand, aren’t as good at maintaining the health of your plants, according to some aquarists.

Choose a broad spectrum of illumination with additional colors if you use this option.

This way, you can ensure that the plants receive all the red, green, and blue frequency ranges required to photosynthesize efficiently.

If you are still confused about choosing the best lighting for your aquarium, let’s check this video out:

planted aquarium

Lighting color options for aquariums

Final Thoughts

Can fish see blue light? Yes, they may see blue light. It is shown through their behavioral changes when you turn on this lighting.

Besides this color, you can consider other options like red or white light, depending on your tank conditions and preferences.

Remember that you shouldn’t leave the light at night, which may negatively affect your pets.

If you have further questions, please leave a comment below. We will answer them all. Thanks for following this post!