Do fish sleep? How do fish sleep in water? Whether you own a fish or not, these questions might come to anyone’s mind!

Shimmering and colorful fish are aquatic vertebrate animals that happily swim in the deep blue waters, weave through coral reefs, and dance among the gentle swaying of seagrass.

Today we can see fishes in every imaginable and unimaginable color, pattern, and shape. From tiny goldfish to large sharks, there are over 34,000 species present today! With their constant swimming and aquatic adventures, we often wondered, do fish ever take a break?

If you have betta fish or goldfish, you might be wondering, do betta fish sleep or do goldfish sleep? Keep reading to learn about the interesting facts about these wonderful aquatic marvels!

Today in this post, we’ll tell you everything about the sleeping habits of fish. From the sleeping stages and routines of fish to where and when fish sleep, we’ve covered every topic related to the sleeping habits of fish.

So, are you ready to unlock the secrets of underworld world creatures?

Let’s start with the most asked question.

Do Fish Sleep?

Well yes! However, the way a fish sleeps is completely different from the way we sleep.

Researchers are still finding how fish brains work during sleep and their sleeping patterns. This is because sleeping is quite different for fish as compared to other animals, even sea creatures.

As underwater world creatures, fish are usually more alert than humans during sleep. There are several threats in water, so being aware can give them more time to react in any dangerous situation.

However, the most fascinating thing about fish is that even though they are attentive in their sleep, they can slow down their metabolic processes as if they are in a state of rest. These marine animals also physically slow down, so they often seem just floating in one place. (which many people consider a glitch in the Matrix!)

What Are The Sleep Stages of Fish?

What Are The Sleep Stages of Fish

Just like us, fish also have various stages of sleep. Humans have basically four stages of sleep: two are light sleep stages and one stage of slow-wave, deep sleep, and one stage of rapid eye movement (REM) sleep.

Fish don’t have a neocortex like humans, but scientists can still monitor brain activity, heart rate, and eye and muscle movement. With the help of these things, they’re able to determine the two stages of sleep of fish.

So, basically, a fish has two stages of sleep:

  • Slow-wave Sleep (Alert Rest): In this type of sleep, the brain sleeps, but all the senses are active. This helps fish to remain alert for threatening situations.
  • Paradoxical Sleep (Deep Sleep): This is the actual sleep stage, where both fish are completely at rest, and their body is “on standby.”

How Do Fish Sleep?

From slowing down their breathing to floating in the same place, fish sleep differently like other mammals, birds, and reptiles.

Researchers at Stanford University discovered that Zebra Danios sleep in the same way we do.

The major difference is that during deep sleep or during paradoxical sleep, they did not exhibit Rapid Eye Movement (REM), which humans and other animals have.

Do Fish Close Their Eyes When They Sleep?

Do Fish Close Their Eyes When They Sleep

You might have noticed that fish don’t close their eyes at all! So, do fish sleep at night? Or do fish sleep with their eyes open?

Yes, fish sleep at night but don’t close their eyes because they don’t have eyelids!

Most fishes become motionless during deep sleep; however, some species of sharks keep moving to ventilate their gills.

What about betta fish? Do betta fish sleep? How do betta fish sleep?

Here are some more interesting things about betta fish and other fish sleeping patterns:

  • Betta fish sleep at night but their eyes and fins are open, and they also lose color. They do this to protect themselves from any predators or parasites.
  • Betta fish can also sleep in various positions. So, if you own a betta fish, and you notice them curled up like a cat, don’t freak out! This is just one of their sleeping positions.
  • Marine Parrot fish and Wrasses species of fish always surround themselves with a mucus cocoon, also known as a “sleeping bag,” when they go to sleep.
  • A betta fish can sleep around 12-14 hours a day, apart from their short naps during the day.

Where Do Fish Sleep?

After knowing the fact that fish can sleep, the next thing that comes to your mind is: do fish sleep upside down if you own an aquarium; how do fish sleep in a tank, and do fish sleep at the bottom of the tank?

Where a fish sleeps usually differs from species to species. Nurse sharks like to lay on the bottom of the tank, while some bury themselves completely in the sand. Many fish species, like Parrot fish, hide in caves or under grottos to protect themselves from predators or rest in a group.

However, most of the time, fish just hover or drift along motionlessly around plants, corals, or near the surface.

When Do Fish Sleep?

When Do Fish Sleep

Biologists say fish have a similar sleep schedule to humans, mammals, and other animals.

Most aquarium species are diurnal, meaning they swim all day, and at night they just sleep. This is why it’s so fun to watch fish during the day!

However, some kinds of fish, including catfish, plecostomus, knife fish, and loaches, are nocturnal, meaning they are more active at night. They usually hide and sleep in caves or crevices during the daylight hours and can be found prowling at dark hours of the day.

This is why it’s advised not to put diurnal and nocturnal fish together in the same aquarium.

Here is another thing to remember: some kinds of fish, like Tilapia, don’t start sleeping until they are about 6 months old. Similarly, wild fish don’t like to sleep at the time of migration. Another type of fish that really doesn’t sleep at all is blind cave fish because they live in dark areas of the sea, so they don’t know when it’s day or night.

How Long Do Fish Sleep?

If you own a betta fish, you might be curious to know how long do betta fish sleep.

The sleeping time of a fish usually depends on the aqueous environment and type of fish species. Some fish take short but frequent naps during the day and night. On the other hand, others sleep for long hours only at night.

Another interesting thing about fish is that, just like us, fish also sometimes sleep at specific times when they’re taking care of their babies or migrating.

The sleeping schedule for aquarium fish is also not certain. It’s not confirmed whether they synchronize their biorhythm with the switching on and off timing of the tank. So, you can also set a sleep schedule for your fish by turning on and off the aquarium lights at a specific time every day.

How Can You Tell When a Fish Is Sleeping?

How Can You Tell When a Fish Is Sleeping

Whether it’s you or your fish, everybody needs to get proper sleep to remain happy and healthy. But fish don’t sleep in a bed like us, so sometimes it’s a bit harder to figure out whether your fish is really sleeping or just floating in the aquarium.

Here are some ways to know whether your fish are sleeping:

  • They are floating in the same place or have not moved for a few minutes.
  • They keep floating at the top or bottom of the aquarium.
  • You have not seen them for a few minutes or hidden beneath coral or plants or in a cave for quite some time.
  • They are less active or do not react to things at all.
  • They exhibit the same behavior at the same time every day or when you turn off the tank’s light.

Just look at the above signs, and if your fish are doing the same things, they’re surely sleeping or taking a nap.

How Do I Make Sure My Fish Get Enough Sleep?

As a pet owner, it is obvious that you want to make sure that your fish stay healthy and live a long time. And good sleep plays an important role in this. You can do this by providing a proper sleeping routine for your lovely fish. First, buy a large aquarium where your fish live comfortably. You can also install lighting in the fish tank but turn it on and off at the same time. Those who do not want to put lights in their aquarium can go with curtains.

Do Fish Sleep: Final Thoughts

do fish sleep

You might have seen fish sleep at night if not in real life but surely in movies and animated cartoons. This is actually true! Fish do sleep, but their sleeping schedules or sleep cycles are different. Each species has different breathing patterns; hence they have different ways to take rest.

I hope this guide on fish sleep schedules has given you all the information about the sleeping habits of a fish. Now you can take care of your lovely fish in a better way. If you find this blog informative, share it with your friends, family, or anyone who owns fish.

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