Do Betta Fish Like Blue Light At Night? – Or Is it Too Much?

blue black mixed color betta fish

Your betta tank lighting system (for both day and night) dictates how happy this fish will be. Maybe that’s why it’s one of the hardest parts of fish-keeping. Some aquarists only rely on blue light. It’s better than the harsh white light. But when you are picking a light specifically for the nighttime, you have to think beyond this.

Betta fish love blue light during the day. It boosts their mood and helps them focus on hunting. But it’s not the ideal light color for the night. the fish needs something warmer and more soothing for a sound sleep.

Bettas don’t have eyelids. So, what kind of light the tank has is a huge deal. Keep reading if you don’t want the fish to pass days in discomfort. We have some useful tips for you.

Key Takeaways

  • Betta fish are hyper-active under blue light.
  • Blue light works best for a betta-tank during the day.
  • The shorter wavelength of a blue light can overstimulate a betta.
  • For nighttime lighting, you want something more relaxing and soothing.
  • Warmer tones like red or yellow work best for this purpose.

Do Betta Fish Need Light At Night?

First things first. Betta fish doesn’t require lighting during the night. But it’s still better to offer dimmed lighting to avoid pitch-black darkness. Bettas prefer a consistent day and night pattern in their tanks. A 12 – 14 hours daytime (with bright lights) followed by a dark period is the best way to encourage sound sleeping habits.

See also  Do Betta Fish Glow Under Black Light?

So, if you are wondering what kind of light bettas need at night, the answer is none. You should reduce the brightness level of the existing aquarium light. Make sure it imitates the sunset vibe into the tank. that’s one way of telling your fish when the night begins. Soon, you will watch the fish relaxing and trying to sleep.

 But how do you know if the light is dimmed enough? Well, certain behavior patterns will tell you everything you need to know. For example, the betta will not sleep uninterrupted for a long time. You will see it swimming abruptly and showcasing frenetic behavior. The level of stress and anxiety (for not being able to rest) triggers such actions.

blue white gorgeous betta fish
Owner: Sean Aurellio

Is Blue Light Okay For The Nighttime?

Wavelength from 380 nm to 500 nm is designated as blue light. Blue-colored lighting is very popular for any fish aquarium. Primarily, the blue color brings out the betta’s color better. The fins and stripes on the body look more vibrant.

Apart from that, blue has a shorter wavelength compared to green, yellow, or red. Shorter wavelengths penetrate the eyes more efficiently and don’t lose their color after being absorbed into the water. So, we can say that bettas can see blue light in an intact form (not distorted like red light). It actually stimulates their brain and makes them feel “more awake.” It’s not very different from a human mind.

Lights with blue undertone is used in office or factory as well (for the exact same reason). Blue-colored light would be a great option in the daytime. That’s when you want the fish to be active and swim. Blue light does just that. But we won’t recommend it for the night. The sole reason would be to help the fish calm down before sleeping.

See also  Can A Light Be Too Bright For A Betta Fish?

With the tank filled with blue light, the fish will be overstimulated. That’s not an ideal setup for nap time. the lighting must be dimmed and soothing. Unfortunately, blue light has nothing but soothing properties. If you don’t want the betta to roam around the tank deprived of a good night’s sleep, avoid blue light in the night.

Which Colored Light Is Best During The Night?

As we have said, try something soothing or relaxing during the night. Plus, the lighting must not be “in its face.” We mean the brightness level has to be low. We prefer using red or yellow light (warm undertones). These colors exist at the larger end of the wavelength for the visible spectrum. Such colors easily lose their intensity after being absorbed into the tank.

So, it automatically gets dimmed before hitting the betta’s eyes. That’s why experts suggest warm lighting shades for nighttime. In short, choose anything between the red and yellow spectrum. Don’t go for colors on the “cooler” side. As for bright white light, we don’t consider it ideal for the night.

White light is hardly available in the wild. the sunlight is usually warmer tone. Considering that natural light has to pass through layers of water, the brightness stays low. But that would be hard to imitate using bright white light. We are afraid it would be too harsh even during the day.

cornflower blue betta

Is Black Light Okay For The Night?

We have covered almost every color of light. But what about the black lights? It means no light, right? Humans can’t see anything after turning ON a black light. It radiates UV-A waves, which are not captured by the human eye. Its specialty is that once the light hits a betta, the fish absorbs and reflects some portion of the light.

See also  Are Betta Fish Afraid Of The Dark? – Should The Lights Be On?

By the way, the reflected light has a larger wavelength than the original UV-B light. That’s why we can see the fish glowing in the dark. It’s a unique experience.

Black lights are mostly used at night. Technically, it’s perfectly safe to use. However, some people complain that prolonged exposure to harmful UV-B radiation causes bleeding and other health issues in the betta. If you really want to try the black light effect, please ensure the radiation is in the safe zone. Otherwise, you are putting your fish at great risk.

Before You Leave!!

It’s really thoughtful of you to consider a comfortable night light for your betta. But daytime lighting is as much important if not more. You can read our next article on “What color light do bettas prefer?” to get a proper understanding of this topic.

Sharing is caring!

Muntaseer Rahman

About Author

Hello, I’m Muntaseer Rahman, the owner of I’m passionate about aquarium pets like shrimps, snails, crabs, and crayfish. I’ve created this website to share my expertise and help you provide better care for these amazing pets.


This site is owned and operated by Muntaseer Rahman. is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to This site also participates in other affiliate programs and is compensated for referring traffic and business to these companies.