If a person has aquarium fish, he can constantly observe their wakefulness. When people wake up in the morning and fall asleep at night, they see them slowly swimming around the aquarium. But has anyone ever thought about what they do at night? All inhabitants of the planet need rest and fish are no exception. But how can you tell if fish are sleeping, since their eyes are always open?
“Fish” dream and everything connected with it
When thinking or talking about sleep, a person represents a natural physiological process of the body. With it, the brain does not react to any minor environmental factors, there is practically no reaction. This phenomenon is also typical for birds, insects, mammals and fish.
A person spends a third of his life sleeping and this is a well-known fact. In such a short period of time a person completely relaxes. During sleep, the muscles are completely relaxed, heartbeat and breathing decrease. This state of the body can be called a period of inactivity.
Fish, due to their physiology, differ from the rest of the inhabitants of the planet. From this we can conclude that their sleep occurs in a slightly different way.
- They cannot switch off 100% during sleep. This is influenced by their habitat.
- In an aquarium or open water The fish do not become unconscious. To some extent they continue to perceive the world even during rest.
- Brain activity does not change in a relaxed state.
According to the above statements, we can conclude that the inhabitants of reservoirs do not fall into deep sleep.
How fish sleep depends on whether they belong to a particular species. Those who are active during the day are motionless at night and vice versa. If the fish is small, it tries to hide in an inconspicuous place during the daytime. When night falls, she comes to life and looks for something to profit from.
How to recognize a sleeping fish
Even if the representative of the water depths is shrouded in sleep, she cannot close her eyes. Fish do not have eyelids, so water constantly cleanses the eyes. But this feature of the eyes does not prevent them from resting normally. At night it is dark enough to enjoy your holiday peacefully. And during the day he chooses fish quiet places, into which a minimum amount of light penetrates.
A sleeping representative of marine fauna simply lies on the water, while the current continues to wash the gills. Some fish try to cling to leaves and branches of plants. Those who prefer to relax during the day choose shade from large plants. Others, like people, lie sideways or with their bellies directly on the bottom. The rest prefer to remain in the water column. In an aquarium, its sleeping inhabitants drift and do not create any movement. The only thing that can be noticed is a barely visible swaying of the tail and fins. But as soon as the fish feels any impact from the environment, it returns to its normal state with lightning speed. This way, the fish will be able to save their lives and escape from predators. 
Sleepless night hunters
Professional fishermen know well that burbots do not sleep at night. They are predators and forage for food when the sun goes down. During the day they gain strength, and at night they go out hunting, moving completely silently. But even such fish like to “rest” for themselves during the day.
An interesting fact is that dolphins never fall asleep. Today's mammals were once classified as fish. The dolphin's hemispheres turn off one by one for a while. The first is 6 hours and the second is also 6. For the remaining time, both are awake. This natural physiology allows them to always be in a state of activity, and in case of danger, escape from predators.
Favorite places for fish to sleep
During rest, most cold-blooded animals remain motionless. They love to sleep in the bottom area. This behavior is characteristic of most large species living in rivers and lakes. Many people claim that all aquatic inhabitants sleep on the bottom, but this is not entirely correct. Ocean fish continue to move even during sleep. This applies to tuna and sharks. This phenomenon is explained by the fact that water must wash their gills all the time. This is a guarantee that they will not die from suffocation. That is why the tuna lies down in the water against the current and rests, while continuing to swim.
Sharks don't have a bladder at all. This fact only confirms that these fish must be in motion all the time. Otherwise, the predator will sink to the bottom while sleeping and, in the end, will simply drown. It sounds funny, but it's true. In addition, predators do not have special covers on their gills. Water can enter and wash the gills only while moving. The same applies to stingrays. Unlike bony fish, constant movement is, in a way, their salvation. To survive, you need to constantly swim somewhere.
Why is it so important to study sleep habits in fish?
For some, this is just a desire to satisfy their own curiosity. First of all, aquarium owners need to know how fish sleep. This knowledge will be useful in providing suitable living conditions. Just like people, they do not like to have their peace disturbed. And some suffer from insomnia. Therefore, in order to provide the fish with maximum comfort, it is important to observe several points:
- before buying an aquarium, think about the accessories that will be in it;
- there should be enough space in the aquarium to hide;
- fish should be selected so that they all rest at the same time of day;
- It is better to turn off the lights in the aquarium at night.
Remembering that fish can “take a nap” during the day, the aquarium should have thickets in which they can hide. The aquarium should have polyps and interesting algae. You also need to make sure that filling the aquarium does not seem empty and uninteresting to the fish. In stores you can find a huge number of interesting figures, including imitation of sinking ships.
By making sure whether the fish is sleeping and finding out what it looks like, you can create comfortable living conditions for your pets.
Owners of aquarium pets rarely think about how fish sleep. The eyes of underwater inhabitants always remain open, so it seems that they never fall asleep. However, this is not entirely true. Fish, like most living creatures on the planet, need rest to recuperate, but they do it in a very original way.
The eyes of underwater inhabitants always remain open, so it seems that they never fall asleep.
Day and night sleep of fish
Most creatures living underwater have eyes that are designed differently than their terrestrial counterparts. They do not need eyelids and eyelashes to constantly keep the iris hydrated; their permanent habitat does this perfectly. That is why fish sleep, just like they are awake - with their eyes open.
The state when all processes occurring in the body are suspended is usually called sleep. During this period, not only the heart rate slows down, but also brain activity decreases significantly. For most fish this occurs at night, but there are also species that prefer to rest during the day. These are usually nocturnal hunters such as catfish or pike.
In order to understand whether aquarium fish sleep at night, just watch them for a few minutes in the dark. Pets are in the arms of Morpheus if:
- remain in one place for several minutes;
- hiding among plants or stones;
- lie on their side motionless at the bottom of the aquarium.
This condition is also typical for sick fish, so you should be wary if it occurs during the day or continues long time.
If the fish remain in one place for several minutes, then most likely they are sleeping.
Wild inhabitants of reservoirs
While it is quite easy to see at night whether fish are sleeping in an aquarium, what their relatives are doing in open water is much more difficult to find out. It turns out that it all depends on the type of waterfowl. Not all of them prefer to rest in the dark, but even those who do choose their own way. For example:
- cod prefers to lie on the bottom with its belly down;
- herring often sleeps with its belly up, hovering in the water;
- flounder likes to bury itself in mud or sand;
- Most sharks doze while moving because they do not have an air bladder.
Do fish sleep at night? good sleep or just dozing, it’s very difficult to understand. After all, in case of any danger, they are ready to immediately interrupt their rest. It is believed that their brain is always in a state of wakefulness Therefore, the reaction to external stimuli in fish is almost instantaneous. It’s easy to check - you just need to turn on a bright light at night and watch the pets in the aquarium.
Features of aquarium maintenance
Before buying an aquarium and having swimming pets, you should carefully study all the nuances of their maintenance. Irresponsible owners rarely think that fish are living beings with their own needs. A comfortable living environment is the first thing an owner should provide for their pets, even if they are just silent creatures in the water. There are three main rules that must be strictly followed when keeping aquarium fish:
- purity;
- correct selection of feed;
- daily rest for pets.
Many owners simply ignore the last point, leaving the lighting on all night, and this can greatly damage the health of the inhabitants of the aquarium. It does not matter whether the fish sleeps at night or prefers to rest during the day, conditions close to their natural habitat must be strictly observed.
Conditions close to the natural habitat must be strictly observed when keeping aquarium fish.
Cleaning an artificial reservoir and timely replacement of water also play an important role in keeping fish. Lack of oxygen can lead to illness in pets and, as a result, to their death.
Excess feed can be just as dangerous as not enough feed. Overeating, the fish become lethargic, move little and sleep a lot. This can disrupt their natural digestion process and kill the pets.
Besides clean water And proper feeding, The design of the aquarium plays an important role. Fish need plants and barriers to be able to rest during the day, as well as properly selected devices to maintain oxygen levels and illuminate an artificial reservoir.
Selection of fish
You can’t just buy an aquarium and put different inhabitants in it. Even ornamental fish have predatory species, and if they are placed together with ordinary fish, it is not difficult to guess how it all might end. To avoid this, you should:
- carefully study the selected type;
- populate the pond with pets of approximately the same age;
- buy different types with the same rhythm of life;
- keep fish that have similar food preferences.
If you follow these simple rules, your aquarium fish will feel more comfortable. After all, if all pets eat and sleep at the same time, this will not only add activity to them, but will also prolong their existence.
Many animals in nature and at home rest differently. Some are standing, some are sleeping lying down or sitting, some are afloat. For example, have you ever thought about how a fish sleeps? These cold-blooded ones also need rest, at least for a short time. Interest Ask, you must agree, no one has ever observed fish with their eyes closed. Why? Yes, because they don’t have eyelids, and they simply have nothing to close them with!
Land animals are forced to moisten the ocular surfaces by constantly blinking. But in a dream it is quite difficult to do this, since control over reactions is lost. Therefore, the eyes of mammals, for example, are closed for centuries during sleep. Fish have a different story: they exist in water, so there is no need to constantly hydrate. But still, like all animals, they are forced to rest. We will tell you how fish sleep in our article. And these representatives of the fauna world sleep differently, which depends on the species and habitat.
How does a fish sleep?
It is known that fish rest differently from the way, for example, mammals do (by the way, it is good to study the behavior of these animals for those who have an aquarium). Pisces sleep, rather, resembles a phase of rest and relaxation, when many body functions slow down and the reaction weakens. Some species of fish turn off their reactions so much that you can literally touch them with your hands and shine a flashlight in their eyes - they still remain immobilized. Some species, on the contrary, in this state can sense danger well.
Where do fish sleep?
During their rest, many species of these cold-blooded animals become practically motionless. They usually rest in the bottom area. This applies to many large river and lake species. But the statement that every fish sleeps at the bottom will not be entirely true. Some oceanic fish species must be constantly on the move, even while sleeping. These include, for example, sharks and tuna. Water must constantly pass through their gills, otherwise they may suffocate. Therefore, tuna lie down on the water against the current and, thus, swim and rest. And sharks - these contemporaries of dinosaurs - do not have a bladder at all, which other types of fish have. This fact is another argument to be on the move even while resting. Otherwise, the shark will simply sink to the bottom and, in the end, no matter how funny it sounds, drown! And also - stingrays and sharks do not have covers on their gills, like many others, so water enters there only when the fish is moving, and they cannot sleep relatively peacefully, as bony sharks do - they need to go somewhere all the time swim.
Features of holidays
The position in which fish sleep largely depends on the species. For example, the astronotus hangs upside down. And the clown fish at the bottom of the aquarium lies on its side. Some aquarium fish simply hang motionless.
How does a fish sleep? In natural conditions, the positions for her rest can also be very different. The flounder digs into the sandy soil at the bottom. Cod sleeps lying down. The herring is completely belly up, floating downstream. Most sleep in secluded places, previously prepared among stones and crevices, corals and algae. And the parrot fish envelops itself in a cocoon of mucus to become invisible to predators.
Duration
How long do fish sleep? Most fish, like many animals, are active throughout the day. With the onset of darkness, life comes to a standstill, and it’s time to rest. That is why, for example, it is so important for fish kept in aquariums to reasonably follow their natural regime. Agree, if you are woken up at three o'clock in the morning by bright light and noise, you are unlikely to like it. The same goes for fish: it is necessary to turn off the artificial one in the evening and at night so that the animals can rest. Otherwise, the number of aquarium fish may be significantly reduced.
Night hunters and those who never sleep
It is typical that some river fish (for example, catfish or burbot) do not sleep at night. They prefer to hunt and rest during the day. However, even among fish that lead a diurnal lifestyle, there are those who like to take a siesta in the middle of the day. But dolphins (mammals that were previously classified as fish) never sleep at all! The hemispheres - left and right - of the dolphin's brain rest alternately (each for about 6 hours). The rest of the time, both hemispheres are awake.
And what do you think? Are they sleeping or not?
In general, from a human point of view of sleep, the sleep process in fish cannot be mistaken for such.
But the fish are SLEEPING! They are alive, and so far not a single living organism has been found that can survive without sleep. They sleep, but in their own way.
Santa Filomena balloon sleeps in the water column.
If you have an aquarium, you can see this with your own eyes.
Here you sit and half an hour You are watching the fish, you have looked through all your eyes, but the fish are swimming in their own eyes and not in one eye.
Catfish pterygoplicht (pterodactel), there was trouble with it. It has grown too big for my 60 liter aqua. In the morning all the water was muddy, the filter was clogged because the pterodactel had been working at night. I had to give it to a large aquarium. Here he is still a baby. Why do we think fish don't sleep? Because they do not close their eyes, but this is physically impossible for them. Because they remain in a state of activity whenever you approach the aquarium. This is how fish are designed, taking into account their habitat. They must always be on guard. They don't have deep sleep.
Fish sleep consists of reducing physical activity and slowing everyone down physiological processes. But their brains don’t turn off. At the first danger, they become active again. They just drift in the water. Small movements of the fins can be seen.
cichlazoma yellow hid in a grotto of stones. You can verify this if you go into the room where the aquarium is and suddenly approach it, especially in the morning. Or turn on the lights suddenly at night. Before this, the motionless fish will immediately react to your appearance.
Moreover, different types of fish sleep differently. For example, our fish: sank to the bottom and froze - guppies; hid in grottoes - cichlids and catfish, slept in the grass.
In general, if you are interested, then, for example, parrot fish make a “cocoon” for themselves to sleep.
Sharks sleep in the current because they need to constantly wash their gills - more correctly, gill slits (they do not have gills) in order to receive oxygen. Otherwise they will suffocate.
How guppies sleep.
The youngest child was less than a year old when we got an aquarium. He stuck around him like he was watching TV. I looked at the colorful fish with pleasure and followed them with my finger along the glass. When he began to move independently and get to the aquarium, the calm life of the fish ended. Mostly they had overfeeding)) This leaked into cleaning the aquarium and filter. Because the young naturalist, with his still naughty hands, poured out half a can of food for them.
Many of us have an aquarium in our home. Watching the beautiful inhabitants of the reservoir, few of us think about whether they ever sleep. In our article we will tell you whether fish are sleeping and how you can determine this.
Why you need to know your sleep schedule
Sleep is a natural physiological state of the body, during which the reaction to the outside world decreases and brain activity is reduced to a minimum.
Important! Make sure that the aquarium is not exposed to too much light, as it will irritate its inhabitants.
This is how people, mammals, birds, some insects and fish sleep. On average, a person spends a third of his life in a state of sleep. At this time, the heart rate decreases and breathing slows down, and muscles relax. Thus, we can say that at this time the body is inactive. Pisces have slightly different biological functions bodies, so during sleep they experience slightly different processes. 
Due to the fact that their habitat is water, as well as due to other external and internal structure, they are not able to completely disconnect from the outside world:
- During sleep, fish are not in an unconscious state; they partially continue to perceive and be aware of what surrounds them.
- During sleep, there are no significant changes in the brain activity of fish.
- Sleeping patterns are important for aquarium inhabitants as they allow them to adapt to environment during life.
Did you know? Length itself small aquarium in the world - 3 cm, and width - 1.5 cm. It contains two small fish, sand, stones and several plants.
For example, some fish hibernate when cold weather arrives. It is characterized by a decrease in metabolic processes, a slowdown of all physical functions. During this period, the fish are mainly located at the bottom of the aquarium. Other types of fish, on the contrary, like to sleep when it’s hot outside. In this way, they try to protect themselves from dehydration.
Do fish sleep in an aquarium at night?
Depending on the type of fish, some of them sleep at night. However, their main difference from all mammals is that they do not close their eyes, since they do not have eyelids. 
You can identify a sleeping aquarium inhabitant by the following signs:
- the fish just lies on the water;
- she is caught on the branches and foliage of plants and is in an immobilized state;
- the fish lies on the bottom with its belly up;
- she hangs in the water column.
Important! Pisces do not fall into deep sleep, so if you notice that they are motionless, you should not make sudden movements so as not to disturb their peace.
Aquarists studied the behavior of fish, their attitude to light and periods of high activity, and divided them into two groups - crepuscular and light-loving.
Twilight
This is a group of night activists who are different good eyesight at night time. Thanks to this feature, they hunt successfully and function easily even without light. But when daylight comes, they try to find shelter for themselves or hide in dense shadows. These include: clown botia, tetradon and others. 
Photophilous
These representatives of the aquarium world prefer a diurnal lifestyle. Their waking period occurs during daylight hours, since they have an eye structure in which they can see perfectly only in the presence of bright light. These fish include: fighting fish, geophagus.
