Do fish sleep?

Do fish sleep? It’s a question that has been around for centuries. Of course, when you’re a fish, there are plenty of things to keep you busy. You need to eat, inhale and exhale, after all. But you’re not a fish, so if you’re forever curious about how fish sleep, here’s what you need to know!

fish sleep

Where Do Fish Sleep?

Fish sleep in the same way humans do: They lie down on the floor of their habitat and close their eyes. Some fish even have particular behaviors they do while they’re sleeping—for example, sharks will move their gills up and down while they’re sleeping so they don’t drown.

Fish sleep in two ways: active and idle. They can rest their eyes, brain, and body by taking brief naps of between 5 and 30 minutes. Most fish rest at night, while they are idle at the bottom of the ocean or lake floor. Inactive fish will also sleep when they are hiding from predators or pausing in shallow waters with low oxygen levels.

When do fish sleep? Depending on the species, a fish might slumber once every few days or every few hours. This is because some fish need more rest than others do—for example, sharks need a lot more rest than goldfish because they spend so much energy swimming around all day long!

Fish sleep when it is dark, and they are not foraging or spooked. Most commonly, this occurs at night when there is no light entering the water’s surface (or indeed under it) and there aren’t any other fish around to scare them awake. However, some species of fish have been observed sleeping during the day as well—it just isn’t as common for them to do so because most predators won’t be around during daylight hours either!

How Do Fish Sleep?

Most fish sleep at night, spending time in the water column when it’s dark. However, some fish live in areas where there are no light changes or even seasons—like the deep sea or lakes that don’t freeze over—and these fish may rest at any time of day.

Most bony fish sleep by resting on the bottom of the ocean floor and keeping their eyes open to watch for predators. Sharks and rays also rest on the bottom of their homes, but they keep their eyes closed during this time. Some species have evolved to sleep with one eye open while using both sides of their brain at once. This allows them to remain alert while sleeping!

Many people believe fish do not sleep, but this is not true. They do, in fact, slumber just like humans do. The only difference is that their slumber patterns diverge from ours.

Fish need to sleep because they are cold-blooded and their body temperature fluctuates with the temperature of their environment. When they are too cold, they become drowsy and fall asleep; when they are too warm or when it’s nighttime, they become active again.

The time that fish sleep for varies depending on their species. Some fish only require about 20 minutes of slumber at a time, while others need over six hours at a time!

Sleeping patterns

Fish are unique creatures that can adapt to their environment in a variety of ways. One of the most interesting adaptations is the way that different species of fish sleep. Depending on their habitat, fish can exhibit different patterns of sleep.

One of the most common sleeping patterns observed in fish is known as vertical swimming. This pattern is seen in most open water fish, such as tuna, mackerel, and salmon. This type of sleep is characterized by the fish remaining in a vertical position in the water column, with their fins extended and their body motionless. This form of sleep allows the fish to remain alert and avoid predators while they rest.

Another common sleeping pattern is known as torpor. This is seen in many species of bottom dwelling fish, such as cod and flatfish. Torpor is characterized by the fish becoming sluggish and almost motionless in the water. They remain at the bottom of the water column, with their fins tucked in close to their body. This form of sleep helps the fish conserve energy and remain hidden from predators.

A third type of sleeping pattern is seen in some freshwater species. This pattern is known as surface swimming. In this pattern, the fish swim near or at the surface of the water, with their fins spread out. This allows the fish to remain alert to predators and take advantage of any food sources that may be present. This is a common behavior for species such as carp, catfish, and bass.

Finally, some species of fish exhibit a fourth type of sleeping pattern known as bottom resting. This behavior is seen in many species of benthic fish, such as flounder and sole. In this pattern, the fish remain in a stationary position near the bottom of the water column, with their fins tucked in close to their body. This form of sleep allows the fish to remain hidden from predators while they rest. In conclusion, different species of fish exhibit a variety of sleeping patterns.

While most fish use one of the four patterns described above, there are some species that may use a combination of the different behaviors.


Sleep provides fish with a variety of benefits and can even improve their lifespan. The first benefit of fish sleep is that it helps the fish to maintain their energy levels. During sleep, they don’t expend energy, so this allows them to conserve energy for future activities. Fish also experience a decrease in their metabolic rate during sleep, which helps them to conserve energy. This can be especially beneficial for fish that don’t have access to a large food supply.

Fish sleep is also important for the fish’s mental health. During sleep, fish can process the information they have gathered during the day. This helps them to remember important things and can even help them to learn new skills. Sleep also helps the fish to relax and reduce their stress levels, which can help to improve their overall health.

Fish sleep can also help to improve the fish’s lifespan. Studies have shown that fish that sleep regularly tend to live longer than those that don’t. This is likely due to the fact that sleep helps the fish to reduce stress and conserve energy, both of which are important for a longer life.

Finally, fish sleep helps to regulate the fish’s body temperature. During sleep, the fish’s metabolism slows down, which helps them to maintain a constant temperature. This helps to keep the fish healthy and comfortable.


Like humans and most living beings, fish need to rest and get enough sleep to maintain their health and energy levels. However, unlike humans, fish do not have eyelids and are unable to close their eyes when they sleep. This makes it important for fish owners to create an environment that helps their fish get the rest they need.

In the wild, fish find places to hide and rest during the day, such as among aquatic plants or in the shadows of rocks. To recreate this in an aquarium, owners can provide plenty of hiding places, such as rocks and logs, for their fish to take cover in when they need to sleep.

Owners should also ensure that their fish have a regular light cycle. A good rule of thumb is to keep the lights on for 8 to 12 hours a day and off for 12 to 16 hours a day. This will give the fish time to rest and sleep. In addition, owners should feed their fish at the same time each day. This will give their fish a consistent schedule and help them regulate their sleep-wake cycles.

Finally, owners should keep the aquarium temperature consistent. Fish are more likely to rest and sleep when the water temperature is between 70 and 75 degrees Fahrenheit.