Can Betta Fish See in the Dark

Can Betta Fish See in the Dark

Can Betta Fish See in night-time and the Dark?

Every species of fish vary in terms of their physical abilities whether they are in the wild or living as pets. Pet owners need to know how to properly care for their pets so they can live happily and healthily.

They must learn how fishes live and what their physical attributes such as weaknesses and strengths. For betta fish enthusiasts, these kinds of fish are superior and need special care for them to grow and live longer.

How Betta’s Eye Works

Betta fish rely on their sights to capture or acquire their food. They need to have their line of sight toward their intended prey. They cannot survive for long if they are exposed to dark environments without any hint of light since light helps them see clearly.

Their eyes have monocular vision, which means each eye can see different visions at the same. Unlike human eyes which have binocular vision, they can only focus on one direction at a time. Bettas also have the ability to see black and different colors wherein other aquatic animals do not have this characteristic.

Slow Iris Functionality

Betta’s eyes are naturally slow to adjust in terms of the changes in light intensity. It takes about 30-60 minutes for their iris to adjust. The iris is responsible for the amount of light allowed to reach the eyes. In this case, betta cannot handle the abrupt changes from darkness to brightness.

It will eventually harm their eyes and can cause serious damage. It is preferred to place tanks or aquariums near a window so that they can have enough time to adjust as the day goes into night and night becomes day. If being near a window is not possible for some pet owners, an aquarium light can mimic the rays of the sun telling them it is daytime already. It is important to not abruptly turn on their aquarium light and just turn on another room light for about an hour before.

Betta Eyes Characteristics

Betta eyes are found on each side of their heads. They are round and beady and look like they are popping out like bubbles. The center of their eyes is black which is known to be the iris. It is surrounded by different colors depending on the different types of betta fish. Betta does not have eyelids and cannot blink. Their eyes can see from behind going towards the front. They are also near-sighted which helps them in their combat fighting with other bettas.

Monocular Vision and Lateral Lines

Monocular vision for bettas allows them to see different visions from each eye. Although they have this ability, the disadvantage to this is their depth perception. They can only be near-sighted and cannot perceive anything that is 14 or more inches away. Distant objects are not visible to bettas even though these objects are very colorful.

Bettas are known to have lateral lines or pressure sensors on the side of their bodies to help them navigate in the dark. These pressure sensors are made up of tuned perception cells that can detect any motion in their immediate environment. These lateral lines can also help them capture food and also alert them of any danger in their surroundings. This ability is most appreciated by betta fish in the wild as they are more prone to having predators in the dark.

A Day in a Life of a Betta Fish

The same with human beings, bettas function better during daytime or under the presence of light. They actively swim around and hunt for food when there is light as they greatly rely on their sights for these activities.

Light also helps them maintain a healthy lifestyle as it is needed for their body’s regeneration. It is advisable to expose bettas in brightness for about 14-16 hours a day wherein their feeding time can be scheduled within this time.

During the daytime, they are awake and at night time when everything is dark, they also sleep. Sleeping is also vital for them as they need to be revitalized for the next day’s activities.

They also get tired during the day of swimming and eating. Some researches show that even under extreme or long periods of darkness, bettas can function the same as when they are exposed to light. Some experts would like to counter that the absence of light does not make bettas incapable of having a healthy life.

Betta Fish have Weak Vision in the Dark

The iris in betta fish eyes, the same as other living creatures, is responsible for the amount of light that can enter the eyes. The smaller the iris the lesser the light is being absorbed.

Their iris cannot also immediately adjust to changes in light intensity. Sudden darkness can temporarily blind them as their iris will adjust for almost an hour before being accustomed to the darkness.

It is not advisable to feed betta when it is nighttime or in the dark. They will have a hard time finding the food with just their lateral lines as their guide. Although this characteristic is very helpful in the wild. Bettas can be fed twice a day and it is better to feed them within the 14-16 hour daytime of necessary exposure.

Is Light Necessary for Betta Fish?

Betta fish are active during the daytime. It indicates that it is time for feeding or just swimming around that will stimulate their senses keeping them alert and healthy. But there will always be dangers in having too much or too little exposure to light to these species.

What is too Little or too Much Light?

Having too much light or brightness on betta can overstimulate them which may cause stress or anxiety to the fish. They can become overly aggressive because of their environmental influence.

Too much light can also cause changes in water temperature. It will naturally heat the water that would be uncomfortable to the betta. They also need time for resting as their little bodies need to recuperate from their daytime activities. Like human beings, resting or sleeping is part of their daily lives.

They can sleep well with less light, wherein darkness simply means resting for them.

Less exposure to sunlight or artificial light may weaken their hunting capacities as they need light to seek food. They are diurnal creatures meaning they prefer brightness.

Natural processes in a betta also need light as needed by their bodies. They can be exposed to brightness for about 16 hours a day, the same goes for darkness during their sleeping time. The in-between times can serve as an adjustment period to avoid shocking the bettas.

Why Not Use Natural Sunlight Instead Of Artificial Light?

Excessive sunlight for more than 8-10 hours will allow algae to grow in the aquarium. When there is abundant light and warmer temperatures, algae can naturally grow especially when other factors such as nutrients and proper wind conditions are also present. It is best to alternately use artificial light as well. Although betta fish eat algae, overeating may cause them health problems. The growth of algae will also disrupt the betta’s habitat as they can hinder the fish from finding food.

Also, direct sunlight can cause temperature changes and may heat the water a degree higher. Betta prefers to be in around 75-80 degrees Fahrenheit water temperature. Hot water may speed up their metabolism causing them to age quickly. It will also be very uncomfortable for the fish.

How Much Light Does A Betta Tank Need?

Whether natural sunlight or artificial light, it is best for the betta to have 14-16 hours of light. Some fish owners have timers for the lights on their tanks to ensure that it is monitored. To keep the betta happy and healthy, there must be balance in its day-to-day life with enough food and activities for it to expel its energy. Also, it is important to let it rest and sleep after its long day.

Do Betta Like Colored Lights?

Bettas naturally like passive lights. But there is no certain research that can verify that bettas do not like colored lights. They can see a multi-colored vision and they can see different lights when exposed to them. But these kinds of lights might give off reflection inside the tank that may cause havoc to them. It is best to maintain one colored and subdued light that can mimic sunlight.


Betta fish are diurnal creatures that are active during the day and resting at night. Having sunlight or artificial light will indicate that it’s time for feeding, hunting, or just any activities expelling energy. Beware of having too much light or darkness because both will not be good for bettas. There must be a sufficient balance between the two to avoid stressing them out. And with proper feeding, a healthy and happy betta will be able to maintain its colors and fins.  

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