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Do Betta Fish Sleep? Sleeping Patterns & Behavior

Something I quickly noticed is that my betta fish does not have any eyelids, which makes it very hard to tell if it is asleep. So, do betta fish sleep?

Quick Answer

Yes, betta fish do sleep. They require sleep to recharge their systems just like any other living creature. They should sleep for anywhere between 8 and 10 hours every single night, when it gets dark outside, and then wake up when it is light out. No eyelids can make it hard to tell!

Keep reading to find out everything there is to know about your betta fish and its sleep schedule. I’ll also be talking about a whole lot of interesting facts about your betta fish and sleep.

Do Betta Fish Sleep?

Yes, betta fish sleep, and this is something that they require, just like any other living creature. On average, you can expect a betta fish to sleep for anywhere between 6 and 12 hours everyday, with around 8 to 10 hours being the standard.

wild betta fish orange with black dot

Exactly how long a betta fish sleeps for depends on a variety of factors, including its own energy requirements. Just like all humans are different and might require different amounts of sleep, so do betta fish. Some betta fish may need six hours whereas others might need nine hours.

Getting enough sleep is of course extremely important, and this is true for many different reasons. First and foremost, if your betta fish does not get enough sleep, it won’t have the energy it needs to perform its regular tasks and daily functions. It might be too tired to chase its betta food.

Furthermore, just like with us humans, if your betta fish does not get enough sleep, then its immune system will likely be weakened. 

The recovery of the immune system often depends on getting enough sleep, and without enough sleep, the immune system may not be able to recover fully every night, therefore making the fish susceptible to a variety of diseases. In fact, a lack of sleep can be very dangerous for all living creatures. Eventually, a complete lack of sleep may lead to death.

When do Bettas Sleep?

To say that betta fish sleep when they are tired would of course be a huge oversimplification. The reality here is that betta fish are diurnal creatures, which means that they are active in the day and sleep during the night. This is therefore mainly dictated by the solar cycle, or in other words, the circadian rhythm of the betta fish. For those of you who don’t know, the circadian rhythm refers to the wake and sleep cycle of any living creature, whether betta fish or human beings.

For the most part, especially for creatures in the wild such as betta fish, the circadian rhythm is dictated mostly by the sun. When the sun goes up, creatures wake up, and when the sun goes down, creatures like betta fish go to sleep. This is a natural reaction to light conditions. Most scientists assume that this has something to do with feeding as well, because remember that betta fish cannot see during the night.

Therefore, the only time that betta fish can feed and actively hunt for insects and other foods in the wild is when it is light out, because that’s the only time they can see. Therefore, at home, if you happen to turn your aquarium lights off, you could expect your betta fish to go to sleep, and when the sun comes up in the morning, your betta fish should wake up.

Betta Fish & Sleep – Interesting Facts

I want to provide you with all of the information that you need to know about betta fish and sleeping, just so you are fully prepared.

A Lack of Eyelids

What many people might not realize about betta fish at first, is that they don’t have any eyelids. For many people, this can be somewhat disconcerting, but also confusing. Every time you go to look at your betta fish, it’s eyes are open, which you might assume means that it is awake.

After a few days, it might seem like your betta fish never sleeps. However, once again, this is simply because they do not have eyelids, so they can’t close their eyes, therefore resulting in their eyes looking like they are always open and like the fish is always awake.

Color Changes

Another interesting fact about betta fish and their sleep is that when they rest, they might lose some of their color. Although exactly why betta fish lose some color when they are asleep is not 100% known, they may become very pale or even appear dull while they are asleep.

Don’t worry however, if this lack of coloration goes away once the fish is awake, then there are no problems at all. However, if you just notice that your betta fish is looking a bit dull, it might be because it’s not getting the nutrition it needs, in which case you might want to look into its diet.

Sleep Preferences

Of course, unlike us human beings, a betta fish does not have a nice comfortable mattress it can go rest on. So, what does a betta fish do when it wants to sleep? More often than not, you will see a betta fish hovering somewhere near the bottom of the tank, often near a corner.

They may also float near the surface. Some betta fish even like to rest on or near leaves that might act as beds, or as close to them as possible. In fact, some people even buy so-called beds for their betta fish, which are essentially large fake leaves that betta fish like to rest on. That said, with most betta fish, you’ll just see them floating still somewhere in the tank.

If it’s dark outside and your betta fish isn’t moving much, chances are that it’s just asleep, so don’t freak out and think that it’s dead. If you turn the light on and provide the betta fish with some stimulus, it should wake back up. However, if you turn the lights on and make a bit of noise, but the betta fish doesn’t wake up, then you might have a problem.

Unihemispheric Sleep

Perhaps the most interesting fact about betta fish and their sleep is that they go through what is known as unhemispheric sleep. This actually means that only half of their brain is asleep at a time, with the other half remaining active.

This is thought to be a natural defense mechanism and an adaptation to help them stay alert and deal with potential threats in their natural environments. In the wild, it is eat or be eaten, and if a betta fish is 100% asleep, then it can’t perceive outside threats, and will most likely end up being eaten.

Therefore, at least half of the brain stays at wake at all times, so that the betta fish can be aware of threats as they arise. It might just be the case that this is also the reason why betta fish don’t have eyelids, so their partially active brains can take in information that their eyes view, to help them deal with potential predators.


The bottom line here is that betta fish do require a good deal of sleep every night, and it is therefore up to you to provide them with the conditions they need for a comfortable night’s sleep. You need to have a good aquarium light to provide them with a proper day and night cycle. You also need to provide them with some good places to rest, such as some large leaves.

Providing your betta fish with a clean tank along with stable water conditions is also very important. Make sure that you don’t shine any bright lights on them during the night either, as this will disrupt their sleep schedule. Remember that just like us human beings, betta fish also require enough sleep to be healthy and to thrive.

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