What is a fish dream?
In general, when talking about sleep, we usually mean the natural physiological state of the body, when its reaction to the outside world is reduced and the level of brain activity is minimal.
This happens in humans, mammals, birds, some insects and fish. On average, people spend a third of their lives sleeping (with a sleep duration of eight hours a day). During these periods of time, the heart rate and breathing decrease, and the muscles relax. This state can be considered a period of inactivity.
But fish are very different from others in their biological body functions. Consequently, their sleep occurs in a way that is not quite familiar to us.
- The environment in which they live, as well as the features of the external and internal structure, do not allow them to completely disconnect from the surrounding reality.
- They do not become completely unconscious, and they do not cease to be fully aware of the world around them.
- Their brain activity remains virtually unchanged.
This means that they do not fall into deep sleep.
The sleeping time of these underwater inhabitants depends on the type of fish. Those that are active during the day rest at night and vice versa. For example, a catfish hides in a secluded place during daylight hours, practically does not move, and only with the onset of darkness begins to swim and look for food.
What do fish look like in a dream?
When caught in the arms of a morpheus, fish do not close their eyes. After all, they do not have eyelids, and water constantly cleanses their ocular surface. However, the absence of eyelids does not interfere at all, since it is quite dark at night, and those fish that sleep during the day deliberately swim into shelters or into the shade of plants.
Fish that sleep can simply lie on the water, the current of which will wash their gills. Some may cling to branches and leaves of plants. Others lie belly or sideways on the bottom. Still others hang in the water column. In an aquarium, sleeping fish most often drift at the bottom of the aquarium, making virtually no movements, sometimes barely visible shaking their tail. But with any, even the slightest influence of external factors (be it danger or potential prey), they instantly revive and return to their normal state.
How do fish sleep?
~ Rybka ~
Don't be fooled by the fact that fish's eyes are always open: these living creatures also like to get a good night's sleep and even take a nap in the morning. Can fish sleep? For a long time, scientists puzzled over this question, but the results of a recent study showed that after a restless night, fish like to take a nap. Now researchers have been able to prove not only the fact that fish sleep, but also that these living creatures can suffer from insomnia and also have difficulty with being forced to stay awake. The fish were observed by a group of scientists from the USA and France. It was discovered that when fish fall asleep, their tail fins bend down, and the fish themselves stay either on the surface of the water or at the bottom of the aquarium. When fish are sleeping, they swim much slower. However, their brain biorhythms do not change. They do not have eyelids, so they have nothing to cover their eyes, but during sleep, fish are much less able to distinguish the objects around them. Some fish stop moving when they fall asleep. But others can't afford to stop moving. Tunas, for example, must keep moving because in order to obtain oxygen, water must be constantly passing through the gills. Some fish find secluded corners between rocks or in corals to rest; others actually build a nest for themselves to sleep in. And the parrotfish, when it is about to rest, releases a jelly-like substance that surrounds its body, forming some semblance of protection while it sleeps. Sleeping fish in the water often take strange poses - they bend their heads towards the bottom or seem to fall slightly on their side. https://m-vopros.ru/animals/22/345/ https://www.374.ru/index.php?x=2007-10-17-51
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, fish choose quiet places where a minimal 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 catfish or burbot 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 like 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.
Is it possible to rest “halfway”?
It is easiest for bony fish to sleep, since they, unlike cartilaginous fish, can hang in the water column or sink to the bottom. Some species, such as flounder, bury themselves in the sand before going to bed, and parrot fish sleep in a cocoon of special mucus. Thus, even among marine inhabitants there are those who like to cover themselves with a “blanket” while sleeping.
An interesting way of sleeping is for sea animals such as dolphins, who do not sleep at all. To rest, the mammal “switches off” only one hemisphere of the brain, while the opposite eye closes, and vice versa. The part of the brain that remains active monitors the environment and the breathing process.
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Internal structure of bony and cartilaginous fish
Conventionally, all fish can be divided into light-loving and crepuscular. The former are active during the day, the latter at night. It is not advisable to house them together, as they will interfere with each other’s sleep, plus they have different requirements for the lighting of the aquarium.
Briefly about hibernation in winter and summer
When the cold season sets in, some species of fish go into what is called hibernation. These periods, of course, differ from what we are used to understanding as sleep. But, nevertheless, this is also a sleep cycle.
During it, metabolic processes in the body also decrease, all physical functions slow down, and the fish is inactive. At this time, she either hides in a shelter or remains at the bottom of the reservoir.
And there are also fish that prefer to sleep during hot periods. This way they are protected from dehydration. The phenomenon of hibernation plays a very important role as it helps fish survive outside the water during dry periods or when temperatures are too high.
For example, in Africa there is a fish that wraps itself in mud, thus creating a cocoon, and remains in a state of complete dormancy for up to several months, until the living conditions become suitable again. It is worth noting that aquarium fish rarely resort to such methods.
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.
The fish are sleeping, they are tired. How do fish sleep?
Most fish do not have eyelids, so they cannot close their eyes. But does this mean they don't sleep? The question of whether fish sleep can easily confuse even an experienced aquarium owner, let alone an ordinary person. Most often, this moment interests children, curious why. So, how do fish sleep and do they sleep at all?
Oh those stereotypes
How do fish sleep?
You can understand that a fish has fallen asleep by the following signs: it froze in a thicket or other secluded place, or hovered in the water column. Some can even lie down, and some species prefer to rest on their sides.
Most species of fish prefer to sleep in the dark, so if you go to the aquarium and turn on the light, you will be able to notice how its inhabitants return to an alert state and wake up. But there are also those who rest during the day. These are predator fish, such as catfish.
However, fish sleep is not the state that is meant by this word in people. How do fish sleep? For them, this is not a state of complete relaxation and unconsciousness, like you and I, but rather a process of slowing down vital functions. This allows the fish to become active very quickly if something dangerous or edible appears nearby.
The deep sleep phase, in which there is an almost complete loss of contact with reality, is absent in fish. However, during sleep the nervous system and other body functions are restored.
Do all fish sleep the same?
Only fish of the bony type can hover in the water column and drift during sleep. They manage to do this thanks to the presence of a swim bladder filled with air. The volume of air in this special organ determines at what height the fish will be in the aquarium. The smaller it is, the deeper it will sink into the water column. Most inhabitants of home aquariums are bony fish.
Stingrays and sharks are cartilaginous fish and do not have a swim bladder. How do fish sleep if they cannot hang in the water? They lie on the bottom or rest while moving. Cartilaginous fish suitable for keeping in an aquarium include ancistrus and loachfish.
There are also underwater inhabitants who need to hide in a cave to sleep. Parrotfish sleep very unusually - practically under a blanket. The only thing they use is mucus, which is released by the fish through the mouth. The mucus envelops the carcass, creating a protective cocoon in which you can rest peacefully and not be afraid of anything. In the morning, the fish leaves its “blanket”.
Why do you need to know about the sleep habits of fish?
It is important to know how fish sleep not only to satisfy your own curiosity, but also to provide the fish with comfortable living conditions. Like people, they don’t like it if their routine is violated and they can suffer from insomnia, therefore:
- be sure to turn off the lights in the aquarium at night;
- select the fish so that they sleep at the same time of day.
Please note that there are species of fish that sleep during the day and prefer thickets for this. If you place these in your aquarium, then during the daytime it will look empty and uninteresting.
A couple of interesting facts about the sleep of “wild” fish
In nature, these underwater inhabitants doze in different ways:
- lying belly or sideways on the bottom, like a cod;
- or belly up and head down in the water column, like a herring;
- or burrowing in the sand like a flounder; or wrapped in slime like a blanket, like a parrotfish.
Cartilaginous fish, especially sharks, have the hardest time sleeping.
- They do not have a swim bladder, therefore, they cannot hang in the water column, since without movement they will immediately sink to the bottom.
- And they cannot lie on the bottom either, since they do not have gills, but gill slits, into which water will not enter without movement, and the fish will simply suffocate.
What to do? Here's what:
- some sharks have adapted to sleep in places with bottom currents, constantly opening and closing their mouths to move water around the gill slits;
- other species have squirts (special gill openings located behind the eyes) for this purpose;
- and still others even sleep while walking. At this time, their brain is resting, and the spinal cord regulates the functioning of the swimming muscles.
In conclusion, if you want to see your fish sleeping in the aquarium, suddenly turn on the light at night. And for a couple of moments you can see how they lie on their bellies on the bottom or plants with virtually no movement. This is the “fish” dream.
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How does a fish sleep? Features of the holiday
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. An interesting question, you will agree, because 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 moisturize the eyeball. 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?
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 bony fish, so water enters there only when the fish is moving, and they cannot sleep relatively peacefully, as bony fish do - they need to do it all the time to sail somewhere.
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 upside down, floating downstream. Most bottom-dwelling fish 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 observe 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 lighting of the aquarium in the evening and at night so that the animals can rest. Otherwise, the lifespan of aquarium fish may be significantly reduced.
Night hunters and those who never sleep
It is typical that some river predatory 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.
