Unearth the Truth -Do Aquarium Fish Sleep?

If you are a fish owner, one of the common questions that would have come to your mind is, of course, do aquarium fish sleep? If they do sleep, how can you make out that they sleep? It is quite unusual to find a fish sleeping. Being a fish owner myself, I never knew that they sleep, until I noticed one day that they DO SLEEP, but during different times of the day and each of them have their own sleep schedule.

Fish in aquarium sleep like any other animal would do. Most of the fish are known to be diurnal. They sleep during the night. However, you may also find a few of them that sleep during the day and stay awake at  night. You can tell that a fish is sleeping because when they do, you will find them motionless at the bottom of the tank or at the surface. 

Do Fish Sleep?

Fish do not sleep like we humans do. But, they need rest and they do take rest. They sleep simply by reducing their activity and metabolism. But, sine they do not have eyelids or neocortex in their brain, their sleeping pattern and sleeping behaviour is different from the humans and other animals. 

Recommended Reading – Free or Confined – Is it Cruel to Keep Fish in Tanks?

There have been several studies to understand how fish sleep. It has been observed that the zebrafish is known to sleep like we humans do. Thye exhibit the sleeping patterns similar to us – which includes slow-wave sleep and a type of REM sleep. You can tell that a fish is sleeping, when you find them motionless for a short span of time. When sleeping,  the fish stay at the crevices and similar other hiding places.

How do Fish Sleep?

Unlike humans and other animals, fish do not close their eyes. Thye do not rest in cozy places like most other animals do. They do remain in floating and can stay at the bottom of the tank. Some fish like sharks do need tp keep moving even when they are sleeping.

Fish generally sleep by slowing down their activities. They slow down their movements, brain activity, and breathing. You would generally find them motionless, making only a few occasional movements. Not every fish shows the same sleeping behaviour, they may show different sleeping patterns when sleeping. However, one of the most common symptoms that your fish is sleeping is that they drift along thee water and will not have their regular swimming pattern. They may also move to the bottom of the tank and find a safer place to hide and sleep.

When do Fish Sleep?

Most of the fish do have a fixed sleep cycle just like we humans and other animals do. Most of them are diurnal, and sleep during the day. However, there are a few predator fish that may sleep during the day. That is one of the reasons why you should not keep small fish like guppies and larger catfish in the same tank. 

It may be noticed that there are some fish varieties that do not sleep until they get adult. A few of them are known for not sleeping till they reach the age of 5 to 6 months. A few cave fish which are blind do not sleep as they do not know when it is dark. 

The fish do not follow the typical day and night cycle as most other animals do. The sleep patterns of the fish will depend on whether they are diurnal, nocturnal or crepuscular.

• Nocturnal fish – They sleep during the day, and stay active during the night. They have large eyes and have a good excellent eye sight in the dark.
• Diuranal  fish – They sleep during the night and stay active at day. They have limited vision.
• Crepascular fish – These fish sleep during the night, stay active during the day and stay active during the dusk and dawn.

How Long do Fish Sleep for?

The aquarium fish normally sleep for an average of 8 to 12 hours. The sleep time is generally decide by the amount of light. It is ideally advisable to keep the aquarium in darkness for 12 to 16 hours. The time taken by the fish to sleep is dependent on several factors. They do not normally sleep by taking frequent naps than sleeping at a stretch. 

However, the fish in the aquarium do not follow the sleeping habits in the wild. They syncronise their sleep times with the times of switching on and off of the lights in the tank. So, you can make the fish in aquarium develop the habit of sleeping at specific times, by following your circadian rhythm. If you are wondering how long do fish sleep for, you can change their habits or cultivate a new sleeping habit.

Are Betta Fish Nocturnal?

No, Betta fish are not nocturnal. They belong to the diurnal category. Which means Betta fish sleeps during the night and active during the day. However, being the fish with low energy, Betta fish takes a lot of naps throughout the day. 

However, the long fins on such a short and small body makes the Betta fish to take rest on things such as decorations. If you do not provide your Betta fish with things like a leaf or log, they may move to the bottom of the tank to get enough rest. You may also find it floating on the surface at times. They may also hide inside a decoration.

Do All Aquarium Fish Sleep?

While fish do not sleep in the same way as the other animals do, all the fish sleep for taking rest. Some fish may not go into the state of complete rest, but will rest by minimising their activity and reducing metabolism. They remain alert for staying careful about the dangers. 

Sharks never go into deep sleep. They need to keep swimming to get oxygenated water. Some studies have shown that some fish sleep intermittently even when  they share same genetics. However, they do sleep for some time or take naps as sleep deprivation can make them develop health issues.

Do Fish Sleep at the Bottom of Tank?

Yes, more often than not, fish sleep at the bottom of the tank. However, some of the fish may choose to sleep at the top or on the decorations. Some may even sleep on the filter or other decorations. 

However, sleeping alone cannot be a reason for the fish to stay at the bottom. It can even choose to stay at the bottom if it belong to the bottom feeding variety. A disease or health issue may also be a few causes that can make this issue come up. If your fish stays at the bottom of the tank for prolonged periods of time, maybe you need to check out the possible reasons such as illness or stress.

How Can You Tell if Your Fish is Sleeping?

It is quite easy to find if fish is asleep. The fish remain motionless and stay at the bottom of the tank, They may also stay at the surface at times. They are also quite slow to respond to the things around them. It is also common to find they may stop responding at all. 

Some signs that indicate that your fish is sleeping –

• They may be observed to remain motionless for longer periods of time.
• They lay near the bottom of the tank or near the surface.
• They fail reacting to the activities around them
• They show the same behavior at the specific time everyday.

Comparing Sleep Patterns: Different Types of Aquarium Fish

There are three different types of sleeping patterns of fish. This classification is based on the time off the day that your fish sleeps.

Closing Thoughts

Does aquarium fish sleep? Has that question ever come up in your mind? The fish do not sleep in the same way as you would do. However, your fish need sleep for taking rest. Knowing the fish activities can help you take a complete care about your fish. We are sure that we have helped you understand the sleeping patterns of your beloved fish. Check out the sleeping habits of your fish and make the best use of the knowledge in taking a good care of your fish.