Can Betta Fish See In The Dark? Do They Need Lights On At Night?

Can betta fish see in the dark

Bettas are one of the most beautiful and vibrantly colored fish that one cannot stop admiring and experience joy while looking at them in a tank exhibiting their colors and fins boisterously. Despite their aggressive and territorial nature, they are a treat to the eyes and senses. But if you are on this page, “can betta fish see in the dark” because you want to know if you should let the lights on or off in your Betta fish tank during the nightfall.

The haphazard moves of the Betta fish might have given you the way to this question; can Betta fish see in the dark? Like us, do they possess clear eyesight, or is there something else behind it?

Betta fish have impeccable vision under bright lighting conditions; however, they cannot see clearly in the dark. So, Betta fish has a poor vision in the darkness compared to humans. 

Let us read through to learn more about why Betta fish cannot see in the dark.

Can betta fish see in the dark?

Eyesight is of paramount importance for all the species, whether in captivity or the wild. However, this sense organ is particularly crucial in aquatic animals navigating their ways and finding nourishments underwater, and Bettas are no exception.

The structure of the eyes of Betta is pretty similar to terrestrial vertebrates like birds and mammals. However, there lies a difference; Bettas’ eyes are more rounded than other animals. 

Apart from the shape of the eyes, there lies one more thing about Betta that can amaze you; it is their retina; it includes numerous rod cells that allow them to have a monochromatic vision, which means they can see objects in different directions. Also, their considerable number of cones facilitates flawless colored vision. So, it means that bettas can see quite clearly. And even their eyes come with a unique power to distinguish colors.

Does it mean Betta fish can see in the dark? Well, here is a point where they score a little less. Generally, their vision is a bit weak when it comes to darkness. 

Due to their slow iris functionality, their vision becomes relatively poor in the dark. Also, bettas cannot adjust their eyesight easily to various degrees of brightness.

However, don’t worry; they come with unique traits to complement this weakness. Similar to the goldfish, bettas also use lateral lines, running down their bodies, to swim around in insufficient light or no lighting at all.


Can betta fish see their food in the dark?

We understand that the bettas use their lateral lines running down their bodies to swim through the insufficient light or the dark waters; however, we want to know whether they can identify their food as well?

Unfortunately, the answer is NO! A betta fish even cannot spot their food in the dark. 

If the surrounding is too dark, this fish will not see anything at all. However, if there is even a little light passing through their aquarium glass, they can see an outline of the food. But this is also quite debatable. 

Even though bettas possess some pressure sensors that prevent them from bumping against anything dangerous, the effectiveness of these sensors is still dubious when it comes to detecting tiny pieces of food.  

Hence, these fighter fish need minimal lighting to find and hunt their food. So, don’t be surprised if you don’t see them eating at night times. 

It is good that they don’t see in the dark, encouraging them to rest or sleep. Sleep/rest is essential to all living beings to restore and rejuvenate the lost energy.


How do betta fish eyes function?

While questioning whether betta fish see in the dark, we can also find out why they can’t see in the dark despite possessing an incredible retina with numerous rod cells and cones that facilitate perfect colored vision.

Do their eyes function like humans? Well, color perception in bettas’ eyes is quite similar to ours. Like us, bettas can easily focus on a particular object with much precision, which many fish cannot.

But unlike humans, they will see much contrasted and blurrier images. However, even if they see a blurry image, their eyes are powerful enough in differentiating it from other objects through a high contrast image. 

Besides, these fishes cannot contract or dilate their iris swiftly according to the light intensity. On the other hand, our irises quickly dilate under bright or dim light conditions. But it takes at least 30-60 minutes for a betta fish to fully enlarge their iris.

Hence, you do not want to suddenly turn on the lights in your betta fish tank if there is no other light in the room. They cannot protect their pupils from sudden changes in the intensity of light. Therefore, it is always recommended to turn on another light in the room for at least an hour before turning on their aquarium lights. 

Most fishes possess monocular vision, and bettas are no exception to it. Hence, unlike humans, they can see two different images simultaneously with binocular vision. But their monocular vision with eyes placed on either side of their heads is more likely to help them prey.

Bettas, in particular, are predatory species; do not forget they derive their common name Siamese Fighting Fish for no reason. Although they are aggressive and predators, they also fall prey to other aggressive fishes; it’s no surprise as that’s how precisely the life cycle works! Thus, their monocular vision works as a protective gear that allows them to stay alert from any other potential predator. 

While their monocular vision works as a protective gear from potential predators, it also allows them to be robust predators with their capability to focus precisely on a single object.

Aspects of betta fish vision – Day and night cycle


Bettas are pretty active throughout the day when they receive constant sunlight and in your tank with artificial lights along with the sunlight. This daylight makes it easier for them to find, hunt, and eat their food thoroughly. 

However, on the other hand, at night, they rest when there is no light in their natural habitat. Therefore, sleeping is essential to relax and rejuvenate their body aptly. It also helps them restore their lost energy during the daytime. 

Betta fish require a minimum of 10 hours of light every day. Lighting has impressive benefits in keeping up with their bodily mechanisms and natural processes. So, it is better to provide them adequate light for their well-being. But never keep your Betta at a relatively dark place for more than 10 hours. Keeping them in a semi-dark region for an extended period will significantly impact their health.


A popular saying states bettas need enough light even in the darkness. It says that the absence of light can make them inactive. But some studies show that there is no such risk of keeping them in darkness. The argument intensifies when some experts say that while staying in the dark, bettas remain as active and healthy as in the light. 

Nevertheless, further research is being carried out to know whether darkness can affect their health or not. But it is proven that bettas cannot see well enough even to recognize their food in the dark.


Can betta fish see colors? What colors do they see?

In terms of depth or distance, bettas do not get a spectacular view of any object like us. However, they can see different colors quite well when there is light; that’s because they have diurnal retinas, which means their eyes include more cones than rods. Hence, their eyes can easily distinguish different colors. Hence, their eyes can easily distinguish different colors. Some studies show that bettas can see over three hundred colors just like humans, and also they can perceive ultraviolet colors.

However, underwater determines what colors they can see; each color has its wavelength. For example, the colors related to the red hue have a longer wavelength than blue or green hues; colors with longer wavelengths get absorbed in the water much quicker than the colors of short wavelengths. Hence, it’s likely sometimes your Betta may not be able to red color.


However, with nocturnal animals, the rods are more than cones, allowing them to see in the dark but see fewer colors than the diurnal retinas. 

Nature designs and molds every part of the body to their survival needs, be it monochromatic, dichromatic, trichromatic for those in the coral reefs, or even tetra chromatic in some cases, such as creatures in the crystalline seawater. Likewise, bettas thrive in clear, shallow, and large water bodies in their natural habitat; hence, monochromatic vision helps them prey while keeping them from being protected from predators.

Going by this retinal fact, we can confidently say bettas see a wide range of colors; however, it is not yet clear how many colors that range includes; it requires more study to know whether they can see all color ranges. 


Related Readings: 

Lifespan Of A Betta Fish In Captivity – A Betta Fish Care Guide

Can Guppies Live With Bettas? The Precautionary Measures!

Do bettas like to be in the dark?

Bettas are diurnal, meaning they are active during the day or when there is light and sleep during the night or when it is dark, the same as humans; although we now have ways to keep ourselves awake during the night, humans are still diurnal animals.

Unlike nocturnal animals, bettas don’t enjoy being in the dark; this does not mean you want to keep the lights on in your betta tank. Although some aquarists illuminate their betta tank slightly at night, it is not at all a good idea; this will most definitely disturb their sleep patterns.

How would you feel if a shining light fell on your face while you were trying to sleep? Bettas feel just the same.

It is essential to provide light and darkness equally on any given 24 hours period to ensure adequate sleep and rest, not just for your bettas all the other species in your aquarium tank or pond.

So, if you have aquarium lights in your betta tank, it is a good practice to turn off in the late evening or before bedtime and turn them on only 10 to 12 hours later.


What happens if your Betta gets too much light?

We know bettas are active during the day or in the light. 

Exposure to too much sunlight or bright light can cause agitation and build stress in your betta fish, and, at the same time, it can cause feeding-related issues. 

Also, too much sunlight or long hours of light can heat the water to an undesirable temperature, which may not only cause your bettas to be over-aggressive but also alter all the water parameters.

So, it is highly recommended to skip leaving the tank under direct sunlight for too long. Instead, it is better to opt for artificial lighting rather than direct sun rays.

When do betta fish sleep?

Like all diurnals, even Betta fish sleeps at night. Besides, they prefer the regular day and night cycle for their biological function and other daily activities. 

Its biological function occurs naturally in the wild with the day and night cycles; hence, the sleep cycle follows systematically without human interference.

However, when you are housing them in your home aquarium or pond, we recommend you to keep the day and night cycle by opting in for artificial, which is more in tune with their natural habitat so that they can adapt to your home aquarium tanks adeptly.

Suppose, even if you turn off your aquarium lights during the day and keep your bettas in a relatively dark room, there would be higher chances for them to go off to sleep because that’s the way they got accustomed to your created day-night cycle.

However, keeping the aquarium tank in a relatively dark room without any lights on can make them lose their brilliant colors and cause eating disorders; you will affect them with darkness as much as with bright lights. 

So, for your bettas to have a good rest, you would want to provide anywhere between 12 to 16 hours in 24 hours. 


Can betta fish see in the dark? – Wrap up

Well, no, they cannot see in the darkness of their habitat; they have some unique visionary quality compared to many other fishes. Though they have a weaker vision in the dark, they possess a capacity to distinguish a wide range of colors in the light. 

This exotic member from the gourami family exhibits a brilliant monochromatic and color vision under bright lighting conditions. And their monochrome vision is highly responsible for making them one of the greatest aquatic predators.

Besides, the lateral lines running down their bodies help them to navigate through water and sense the danger in the darkness. 

We all know the betta fish is one of the brilliant and colorful species in the aquarium world; it’s not just that they are radiant and colorful; they can also see and detect a wide spectrum of colors and possess remarkable traits that captivates and grips you with them.

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