Fish breath. Fish breathe oxygen dissolved in water. The respiratory organs of fish are gills, consisting of many petals, with blood vessels. The number of gill filaments in each species of fish is different. So, for example, in a perch it is 30 times more than in others. Observing the behavior of fish in water, you can see that the fish either opens or closes its mouth, the same thing happens with the gills, if the gills open, the fish's mouth closes, and vice versa. Thus, the fish, swallowing water, closes its mouth, the water passes into the gill cavity and flows out through the gill slit. It is the blood vessels of the gill filaments that serve the fish to enrich the blood with oxygen.
Each species of fish has its own "minimum" oxygen content in the water. If this threshold is lower than it should be, the fish become lethargic, inactive and die altogether (these are the so-called kills). Some fish (and others), in the absence of oxygen in the water, also swallow atmospheric air. In the respiratory function, for example, the swim bladder, penetrated by a network of capillary vessels, can also participate. But the tench also has additional skin respiration. Enrichment of water with oxygen comes mainly from atmospheric air and depends on many factors: water temperature, the size of the reservoir, the presence of springs and springs, groundwater, as well as the mixing of various layers of water.
When does the bite of fish intensify?
Lowering the water temperature in summer and wind, contributes to a better dissolution of oxygen. At such a time, the fish feel better in those waters in which there was a lack of oxygen before. Improving the well-being of fish, their revival also involves the activation of biting. This once again proves that the angler should be interested in the state and weather forecast for the period of the upcoming fishing.
There is increased activity and increased biting of fish after rain - this has been noticed by many anglers, this is all because raindrops are saturated with oxygen, and increase the total oxygen content in the water, mixing water with air. In winter, fish choose deeper parts of the reservoir with a rocky or sandy bottom, places at the exit of spring waters, at the confluence of streams and rivers. So, our main task was to answer the question: Do fish breathe? Yes, fish breathe! And whether the fish has enough oxygen can be judged by the activity of the fish.
They breathe for the same reason. Everyone needs oxygen. Oxygen is a gas that bodies use to generate energy.
Living beings experience two feelings of hunger - gastric and oxygen. Unlike the breaks between meals, the breaks between breaths are much shorter. People take about 12 breaths per minute.
It may seem that they breathe only oxygen, but there are many other gases in the air. When we inhale, the lungs fill with these gases. The lungs separate oxygen from the air and release other gases that the body does not use.
Everyone breathes out, which the body produces when it generates energy. Just as the body sweats when we exercise, so too does the body exude when we breathe.
Fish also need oxygen to move their bodies, but the oxygen they use is already in the water. Their bodies are not like those of humans. Humans and dogs have lungs, fish have gills.
How gills work
The gills of fish are visible when looking at their heads. These are the lines on the sides of the fish's head. Gills are also inside the body of fish, but they cannot be seen from the outside - just like our own lungs. You can see the fish breathing in the water because its head gets bigger as it takes on water. Just like when one swallows a big piece of food.
First, water enters the fish's mouth and flows through the gills. When water leaves the gills, it returns to the pond. In addition, the fish produce is also removed along with the water when it leaves the gills.
Fun fact: Fish and other animals with gills breathe oxygen because their blood flows through their gills in the opposite direction from the water. If the blood flowed through the gills in the same direction as the water, the fish would not get the necessary oxygen from it.
Gills are like a filter, and they collect oxygen from the water, which the fish needs to breathe. After the gills absorb oxygen (), the gas spreads through the blood and nourishes the body.
That's why it's so important to keep the fish in the water. Without water, they won't get the oxygen they need to stay healthy.
Other respiratory mechanisms in fish
Many fish breathe through their skin, especially when they are born, because they are so small that they don't have specialized organs. Gills develop as they grow because there is not enough diffusion through the skin. 20% or more of cutaneous gas exchange is observed in some adult fish.
Some species of fish have developed cavities behind the gills, which are filled with air. In others, complex organs developed from the irrigated gill arch form and act like a lung.
Some fish breathe air without special adaptations. The American eel covers 60% of its oxygen needs through the skin and ingests 40% from the atmosphere.
How fish breathe underwater - video
Fish can be found in swamps, lakes, seas and rivers of all geographic zones of the planet. They spend their entire lives underwater without experiencing any difficulty in breathing. Most of them do not need to float to the surface to swallow another portion of air. What do fish breathe? What mechanisms help them survive in the aquatic environment? We will talk about the internal structure of fish and the natural tricks of these aquatic animals in our article.
Oxygen requirement
In the aquatic environment, fish are the predominant group of animals. In rivers and oceans, they go through all stages of their biological development - from eggs to adults. At the same time, only a few species can emerge from time to time and inhale atmospheric air, while the majority have adapted to live without it.
But what do fish breathe when they are constantly in the water? Like other vertebrates, they need oxygen to function normally. They "extract" it not from the air, but directly from the water, literally filtering it. To get enough gas, they have to "process" a huge amount of liquid.
The oxygen content in the reservoir is extremely important for their normal functioning, and a lack of oxygen causes oxygen starvation in animals and death. However, the norms of gas concentration for each species are different. For example, tench and carp live in stagnant water bodies and are able to survive even with a weak presence of oxygen (from 4 cm 3 / l to 0.5 cm 3 / l). Trout, salmon, pike perch, on the contrary, are very demanding. They need a gas concentration greater than 7 cm 3 /l.
The perception of fish changes with their age, with the transition from season to season, and also depending on their activity. So, the younger and more mobile the individual, the more it needs oxygen. Needs greatly increase before spawning, when the fish needs a lot of strength and energy. In the heat and during the winter freezing of the reservoir, there is a lack of oxygen, which makes the animals have difficulty breathing.
What do fish breathe? Devices for gas exchange
Just like ours, gas exchange in fish is carried out using the circulatory system. For this, most of them have only one circle of blood circulation and a two-chambered heart, in lung-breathing species there are two such circles. Oxygen enters the heart through the vessels, and it enters them through the gills, which filter the gas from the water.
The respiratory system of fish, in fact, is more efficient than the human one. It is able to filter two to three times more oxygen from the water than the lungs separate from the atmosphere. Basically, fish breathe through gills, but sometimes their work is not enough or conditions do not allow them to be used normally. In this case, other special bodies are connected to them.
There are quite a few additional or alternative ways of breathing in fish. Absolutely all species help themselves, partially carrying out gas exchange through the skin. Some also use the swim bladder, others use the intestines or the caecum in the stomach. Some species have adapted to breathing atmospheric air, for this they use labyrinthine or supragillary organs.
The internal structure of fish: how gills are arranged
Breathing of fish begins with the ingestion of water through the mouth. In the pharynx they have a gill apparatus, in which the further process takes place. The apparatus consists of gill arches located on the sides of the animal. They are supported by gill filaments and stamens. Outside, in bony fish, the arcs are covered with covers.
The gills of fish are connected to numerous blood vessels. Once in the pharynx, water passes through the gill arches, washes the petals and gives oxygen to the arteries attached to them. Enriched blood is sent to the heart and tissues, and from there it returns to the pharynx, where it gives off carbon dioxide to water and takes it out through the gill slits.
Lungfish
As mentioned above, the main instrument for gas exchange is the gills. However, what do fish that are called "lungfish" breathe? These animals are now represented by only one order, which includes six species. They live near Australia, Africa and South America.
Of all the fish, they are the closest relatives of tetrapods. Another feature of them is that in addition to gills, they have simplified lungs. Such an adaptation allows them to live in water bodies with a very small amount of oxygen, and if necessary, get it from the atmospheric air, emerging to the surface.
Labyrinth or crawler fish
Labyrinth fish represent a detachment of ray-finned fish. These include many aquarium species, such as lapius, gourami, Siamese bettas, macropods, labtose and others. In nature, they live in the fresh waters of Africa and Asia.
All of them also know how to breathe air. They do not have lungs, but there is a special organ in the form of a pocket, consisting of many plates. Capillaries approach its walls, with which the exchange of gases takes place. The labyrinth organ is located above the gills of the fish. Thanks to him, animals can exist for several days without water. At the same time, "second wind" is not a convenient addition to the gills. They cannot not use the labyrinth organ, therefore they are forced to periodically emerge from the water, otherwise they risk suffocating.
As you know, fish in their underwater habitat breathe with the help of gills. The water that the fish absorbs through the mouth is passed by the fish through the gill slits, freeing itself from the oxygen dissolved in it.
Oxygen is assimilated by the fish organism very efficiently, much more efficiently than even in land mammals.
True, not all fish breathe exclusively with gills. Some of them absorb oxygen through the skin. There are also fish that can breathe even on the surface of the water.
They do not have lungs, but they have a special organ - the gill labyrinth. It allows the fish to breathe air. But there is one significant minus: yes, such a fish can survive on land, but it cannot stay in the water all the time either, because it needs air to breathe.
Every living being, including fish, needs oxygen to live. It allows chemical reactions in the body of the fish to decompose organic matter. As a result of these reactions, energy is released, which gives life to the entire organism.
How to provide sufficient oxygen to aquarium fish? In principle, oxygen enters the water from the air in contact with it. You can activate this process by artificially creating waves, rifts and rapids in the water with the help of a microcompressor. Also, the plants that usually decorate an aquarium are in a continuous process of photosynthesis, during which oxygen is released into the water. But the downside is that plants emit oxygen only during the daytime, but at night they, like all living beings, absorb it. We must not forget that oxygen in the aquarium is used not only directly for the respiration of fish, but also for the decomposition of various organic waste. So regular cleaning of the aquarium is not only an aesthetic event, but also a procedure that is useful for the health of the fish.
The oxygen requirement of fish can depend on their species and size, the temperature around them, and even the time of year outside.
A particularly strong factor influencing the amount of oxygen contained in aquarium water is its temperature. Everyone knows that gas dissolves in water the worse, the higher its temperature. In principle, the most satisfactory amount of oxygen for most aquarium fish is about 0.60 milliliters per hundred grams of water. Such an oxygen content is possible in water, the temperature of which does not exceed twenty-five degrees Celsius.
The higher the temperature of the water, the less oxygen becomes in it, the more it is required by the fish. Therefore, such a device as an aquarium compressor is a frequent guest in our city apartments. It allows you to quite effectively supply oxygen to a considerable number of fish.
Everything, of course, depends on the type of fish that you keep in your aquarium. For example, goldfish love fresh air especially. But the fish, whose natural habitat is tropical waters, are accustomed to heat, high humidity and low oxygen content in the water. Such fish do not need a microcompressor in an aquarium. In general, the approach here is individual: fish, accustomed to water bodies with a flow, rapidly changing masses of water, need fresh oxygen literally, like air. But for those fish that naturally live in ponds with stagnant water, special aeration of aquarium water is not required.
It is often said that a large number of underwater plants can saturate an entire aquarium with oxygen without any additional aeration. But it is not so. Of course, in all green plants, the process of photosynthesis occurs, as a result of which oxygen is released into the water. But this happens only in sunlight, that is, during the day. At night, they begin to absorb oxygen. In this case, with a large number of plants in the aquarium, the fish can simply suffocate there. So water aeration is still necessary, even if only at night.
All living things need oxygen. They can take it from atmospheric air or water. But They do not have organs as complex in structure as the lungs. But fish have gills. It is they who help to absorb this gas during breathing. At the same time, they function much more efficiently than our lungs, because they are able to take up to 30% of the oxygen dissolved in it from the water. But in reality, fish have many more ways to breathe. All of them have developed as a result of a long evolution and are inherent only in certain species.
How do fish breathe with gills?
Of course, all fish, without exception, have gills. Their form is varied. In some species, these are sacs, in others, plates or petals. But all these devices are aimed at one thing - the creation of a larger surface, penetrated by a dense network of capillaries, with a relatively small amount of space.
Water with oxygen dissolved in it enters through the pharynx at the moment when the fish opens its mouth wide. The gills themselves are rather delicate organs, so a dense gill cover covers them from above. She is also directly involved in breathing. At the moment when water enters the pharyngeal cavity, the gill covers fit snugly against the head. So they prevent the outflow of fluid. When the gill covers open, the pressure changes and water flows into a special cavity. It is permeated with a dense network of blood vessels. straighten out, and the process of gas exchange takes place. Oxygen enters the blood, and not only carbon dioxide is removed from it, but also metabolic products. Water exits the gill cavity through special slits. This is how fish breathe.
Fish that breathe through their skin
Of course, fish breathe with gills. This is known to everyone. But then how to explain the fact that some species that find themselves out of water, in wet grass or earth, are able to live there for several hours? How do fish breathe in such conditions? Certainly not through the gills.
A number of species, such as crucian carp, eel, carp, carp, in the process of evolution have an additional opportunity. They can absorb oxygen through the entire surface of the skin. This is especially true when the level of this vital gas in the water drops to a critical level. Then the gills become ineffective, and skin respiration comes to the fore.
How do labyrinth fish breathe?
Many aquarium owners have noticed how fish breathe. They often swim to the surface of the water and stick their heads out a little. Why are they doing this?
Many varieties of aquarium fish have a specific respiratory organ - a labyrinth. With it, they can actually absorb oxygen not from water, but from atmospheric air. In this case, the fish should at least once every few hours rise to the surface and take a breath. Otherwise, she will die.
The gill labyrinth is located on both sides of the fish's head. It is located above the gills. When a fish swallows an air bubble, it enters the spongy chambers of the labyrinth. Their walls are densely covered with capillaries. Oxygen penetrates into them, which then spreads to all organs and tissues of the body. The gill labyrinth helps fish not only survive in an oxygen-depleted reservoir, but also move to another.
Fish that breathe through their intestines
Perhaps this will surprise many, but there is one type of fish that uses the intestines for breathing. These are catfish of the genus Coridoras. They breathe atmospheric air. Although this is not entirely true. Unlike the same labyrinth fish, they do not have any special organs. able to take in oxygen in his stomach. This is a fish that breathes air. She simply swallows it and pumps it into the swim bladder. This is where the absorption of oxygen takes place.
Fish that can climb trees
So, what fish breathe in the water is quite understandable. But what about those that can be out of water for several days? Do you think they don't exist? Not at all. A striking representative of such fish is the climbing perch. He lives in the Far East.
The gills of this unique fish are designed so that it is able to absorb oxygen from the air. In addition, she has a special structure of scales, which allows her not only to move on the ground, but also to climb trees. Actually, for this feature it got its name.
By the way, this species is far from the only one. There is another fish that can breathe air - this is a muddy skipper. It lives in those parts of Africa where severe droughts are often observed. This fish has developed an interesting way to survive these unfavorable periods. When the reservoir dries up, the skipper burrows into the silt. There he is able to stay without water for several months. Only when the water comes again does he come out of his makeshift shelter. This is what most lungfish do. This group deserves special attention.
Lungfish
Lungfish belong to a very ancient group. Paleontologists find the remains of these creatures in layers and sediments For quite a long time they were considered a completely extinct species. And only after studying the nature of Australia and Africa in the 19th century, a stunning discovery was made. Modern lungfish species have been found. This not only influenced the views of scientists regarding the taxonomy of vertebrates, but also made its own adjustments to
In all lungfish, in addition to the characteristic gills, one or a pair of lungs is also found. It's modified These organs have nothing in common with the lungs of mammals. Their walls are permeated with numerous capillaries, through which gas exchange occurs. Do fish breathe oxygen dissolved in water? Of course. But only when there is enough of it in the water. They need lungs only to wait out a long period of drought, walled up in silt, or in order to move from one reservoir to another. As a rule, they have highly developed fins that can play the role of limbs. So, lungfish can make transitions lasting even several days.