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What is the significance of color in the life of fish? What determines the color of fish? Dogfish is a deadly predator

The color of fish can be surprisingly varied, but all possible shades of their color are due to the work special cells which are called chromatophores. They are found in a specific layer of the fish's skin and contain several types of pigments. Chromatophores are divided into several types. First, these are melanophores, which contain a black pigment called melanin. Further, ethytrophores, containing red pigment, and xanthophores, in which it is yellow. The latter type is sometimes called lipophores because the carotenoids that make up the pigment in these cells are dissolved in lipids. Guanophores or iridocytes contain guanine, which gives fish a silvery color and a metallic sheen. The pigments contained in chromatophores differ chemically in stability, solubility in water, sensitivity to air and some other characteristics. The chromatophores themselves are also not the same in shape - they can be either star-shaped or round. Many colors in the coloration of fish are obtained by superimposing one chromatophore on another; this possibility is ensured by the occurrence of cells in the skin at different depths. For example, green color is obtained when deep-lying guanophores are combined with covering xanthophores and erythrophores. If melanophores are added, the body of the fish acquires Blue colour.

Chromatophores do not have nerve endings, with the exception of melanophores. They are even involved in two systems at once, having both sympathetic and parasympathetic innervation. The remaining types of pigment cells are controlled humorally.

The coloring of fish is quite important for their life. The functions of coloring are divided into protective and warning. The first option is designed to camouflage the fish’s body in the environment, so this color usually consists of calm colors. Warning coloring, on the contrary, includes a large number of bright spots and contrasting colors. Its functions are different. In poisonous predators, who usually say with the brightness of their body: “Don’t come near me!”, it plays a deterrent role. Territorial fish, guarding their home, are brightly colored to warn rivals that the site is occupied and to attract a mate. A type of warning coloration is also the mating plumage of fish.

Depending on the habitat, the body color of the fish acquires characteristic features that make it possible to distinguish pelagic, bottom, thicket and school colors.

Thus, the color of fish depends on many factors, including habitat, lifestyle and diet, time of year and even the mood of the fish.

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Fish have extremely varied colors with very bizarre patterns. A particular variety of colors is observed in fish of tropical and warm waters. It is known that fish of the same species in different bodies of water have different colors, although they mainly retain the pattern characteristic of this species. Take pike, for example: its color varies from dark green to bright yellow color. Perch usually has bright red fins, a greenish color on the sides and a dark back, but there are whitish perches (in rivers) and, conversely, dark ones (in ilmen). All such observations indicate that the color of fish depends on their systematic position and habitat, environmental factors, nutritional conditions.

The coloring of fish is due to special cells located in the skin containing pigment grains. Such cells are called chromatophores.

They are distinguished: melanophores (contain black pigment grains), erythrophores (red), xanthophores (yellow) and guanophores, iridocytes (silver color).

Although the latter are classified as chromatophores and do not have pigment grains, they do contain crystalline substance- guanine, due to which the fish acquires a metallic sheen and silvery color. Of the chromatophores, only melanophores have nerve endings. The shape of chromatophores varies greatly, however, the most common are star-shaped and disc-shaped.

In terms of chemical resistance, the black pigment (melanin) is the most resistant. It is not soluble in acids or alkalis, and does not change as a result of changes in the physiological state of the fish (starvation, nutrition). Red and yellow pigments are associated with fats, so the cells containing them are called lipophores. The pigments of erythrophores and xanthophores are very unstable, dissolve in alcohols and depend on the quality of nutrition.

Chemically, pigments are complex substances belonging to different classes:

1) carotenoids (red, yellow, orange)

2) melanins - indoles (black, brown, gray)

3) flavins and purine groups.

Melanophores and lipophores are located in different layers of the skin on the outer and inner sides boundary layer (cutis). Guanophores (or leucophores, or iridocytes) differ from chromatophores in that they do not have pigment. Their color is due to the crystal structure of guanine, a protein derivative. Guanophores are located under the chorium. It is very important that guanine is located in the cell plasma, like pigment grains, and its concentration can change due to intracellular plasma currents (thickening, liquefaction). Guanine crystals have a hexagonal shape and, depending on their location in the cell, the color varies from silvery-whitish to bluish-violet.

Guanophores are in many cases found together with melanophores and erythrophores. They play a very important biological role in the life of fish, because... being located on the ventral surface and on the sides they make the fish less noticeable from below and from the sides; The protective role of coloring appears especially clearly here.

The function of pigment staves is mainly expansion, i.e. occupying more space (expansion) and reducing i.e. occupying the smallest space (contraction). When the plasma contracts, decreasing in volume, the pigment grains in the plasma become concentrated. Due to this, most of the cell surface is freed from this pigment and, as a result, the brightness of the color decreases. During expansion, the cell plasma spreads over a larger surface, and pigment grains are distributed along with it. Due to this, a large surface of the fish’s body is covered with this pigment, giving the fish a color characteristic of the pigment.

The reason for the expansion of the concentration of pigment cells can be both internal factors (physiological state of the cell, organism), and some factors external environment(temperature, oxygen and carbon dioxide content in the input). Melanophores have innervation. In canthophores and erythrophores there is no innervation: Consequently, the nervous system can have a direct influence only on melanophores.

It has been established that pigment cells bony fish maintain a constant shape. Koltsov believes that the plasma of a pigment cell has two layers: ectoplasm (surface layer) and cinemaplasm (inner layer), containing pigment grains. Ectoplasm is fixed by radial fibrils, and cinemaplasm is very mobile. Ectoplasm determines external form chromatophore (a form of ordered movement), regulates metabolism, changes its function under the influence of the nervous system. Ectoplasm and cinemaplasm, having different physicochemical characteristics, mutual wettability when their properties change under the influence of the external environment. During expansion (expansion), cinema plasma well wets the ectoplasm and, thanks to this, spreads over the cracks covered with ectoplasm. The pigment grains are in the cinema plasma, are well moistened by it and follow the flow of the cinema plasma. With concentration, the opposite picture is observed. The separation of two colloidal layers of protoplasm occurs. Cinematic plasma does not wet ectoplasm and, thanks to this, cinematic plasma
occupies the smallest volume. At the heart of this process is change surface tension at the border of two layers of protoplasm. Ectoplasm by its nature is a protein solution, and cinema plasma is a lipoid like lecithin. Kinoplasma is emulsified (very finely crushed) in ectoplasm.

In addition to nervous regulation, chromatophores also have hormonal regulation. It must be assumed that under different conditions one or another regulation is carried out. A striking adaptation of body color to the color of the environment is observed in pipefish, gobies, flounder. Flounders, for example, can copy the pattern of the ground and even a chessboard with great accuracy. This phenomenon is explained by the fact that the nervous system plays a leading role in this adaptation. The fish perceives color through the organ of vision and then, transforming this perception, the nervous system controls the function of pigment cells.

In other cases, hormonal regulation is clearly evident (coloring during the breeding season). The blood of fish contains hormones from the adrenal gland - adrenaline and the posterior lobe of the pituitary gland - pituitrin. Adrenaline causes concentration, pituitrin is an adrenaline antagonist and causes expansion (dispersal).

Thus, the function of pigment cells is under the control of the nervous system and hormonal factors, i.e. internal factors. But besides them, environmental factors (temperature, carbon dioxide, oxygen, etc.). The time required for fish to change color varies and ranges from a few seconds to several days. As a rule, young fish change their color faster than adults.

It is known that fish change body color according to the color of their environment. Such copying is carried out only if the fish can see the color and pattern of the soil. The following example illustrates this. If a flounder lies on a black board but does not see it, then it is colored not by the black board, but by the white ground visible to it. On the contrary, if the flounder lies on the ground white, but sees a black board, then its body takes on the color of a black board. These experiments convincingly show that fish easily adapt, changing their color to soil that is unusual for them.

The color of the fish is influenced by light. “So in dark places where there is low light, fish lose color. Bright fish, having lived for some time in the dark, become pale in color. Blinded fish acquire dark color. On dark the fish becomes dark in color, on light it becomes light. Frisch was able to establish that the darkening and lightening of the fish’s body depends not only on the illumination of the ground, but also on the viewing angle from which the fish can see the ground. So, if the eyes of a trout are blindfolded or removed, the fish turns black. If you cover only the lower half of the eye, the fish acquires a dark color, and if you cover only the upper half of the eye, the fish retains its color.

Light has the most powerful and varied effect on the color of fish. Light
affects melanophores both through the eyes and nervous system, and directly. So Frisch, by illuminating individual areas of the fish’s skin, received a local change in color: a darkening of the illuminated area was observed (expansion of melanophores), which disappeared 1-2 minutes after turning off the light. Due to prolonged illumination, the color of the back and abdomen of the fish changes. Usually the back of fish living at shallow depths and in clear waters has a dark tone, and the abdomen is light. In fish living at great depths and troubled waters no such difference in color is observed. It is believed that the difference in the color of the back and belly has an adaptive significance: the dark back of the fish is less visible from above against a dark background, and the light belly is less visible from below. In this case, the different colors of the abdomen and back are due to uneven distribution of pigments. There are melanophores on the back and sides, and on the sides there are only iridocytes (tuanophores), which give the abdomen a metallic sheen.

When the skin is locally heated, melanophores expand, leading to darkening; when cooled, it leads to lightening. A decrease in oxygen concentration and an increase in carbonic acid concentration also changes the color of fish. You have probably observed that after death in fish, the part of the body that was in the water has a lighter color (the concentration of melanophores), and the part that protrudes from the water and comes into contact with the air has a dark color (the expansion of melanophores). In fish in in good condition, usually the color is bright and multi-colored. With a sharp decrease in oxygen or in a state of suffocation, the skin becomes paler, dark tones almost completely disappear. But the fading of the color of the fish cover is a result of the concentration of chromatophores and , primarily melanophores. As a result of a lack of oxygen, the surface of the fish's skin is not supplied with oxygen as a result of cessation of blood circulation or poor oxygen supply to the body (the beginning of suffocation), and always acquires a pale tone. An increase in carbon dioxide in water affects the color of fish in the same way as a lack of oxygen. Consequently, these factors (carbon dioxide and oxygen) act directly on the chromatophores, therefore, the center of irritation is located in the cell itself - in the plasma.

The effect of hormones on the color of fish is revealed primarily during mating season(breeding season). Particularly interesting coloring of the skin and fins is observed in males. The function of chromatophores is under the control of hormonal agents and the feather system. Example with betta fish. In this case, mature males, under the influence of hormones, acquire the appropriate coloration, the brightness and brilliance of which intensifies when they see a female. The male's eyes see the female, this perception is transmitted through the nervous system to the chromatophores and causes their expansion. The male's skin chromatophores function in this case under the control of hormones and the nervous system.

Experimental work on minnows has shown that injection of adrenaline causes lightening of the fish's integument (contraction of melanophores). Microscopic examination of the skin of an adrenalized minnow showed that melanophores are in a state of contraction, and lipophores are in expansion.

Self-test questions:

1. Structure and functional significance of fish skin.

2. The mechanism of mucus formation, its composition and significance.

3. Structure and functions of scales.

4. The physiological role of skin and scale regeneration.

5. The role of pigmentation and coloring in the life of fish.

Section 2: Laboratory materials.

Many secrets and mysteries of nature still remain unsolved, but every year scientists discover more and more new species of previously unknown animals and plants.

Thus, snail worms were recently discovered, the ancestors of which lived on Earth over 500 million years ago; Scientists also managed to catch a fish that was previously thought to have gone extinct 70 million years ago.

This material is dedicated to the extraordinary, mysterious and as yet inexplicable phenomena of ocean life. Learn to understand the complex and diverse relationships between the inhabitants of the ocean, many of which have lived in its depths for millions of years.

Type of lesson: Generalization and systematization of knowledge

Target: development of erudition, cognitive and creativity students; developing the ability to search for information to answer questions.

Tasks:

Educational: the formation of cognitive culture, mastered in the process of educational activities, and aesthetic culture as the ability to have an emotional and value-based attitude towards objects of living nature.

Educational: development of cognitive motives aimed at obtaining new knowledge about living nature; cognitive qualities of a person associated with mastering the fundamentals of scientific knowledge, mastering methods of studying nature, and developing intellectual skills;

Educational: orientation in the system moral standards and values: recognition of the high value of life in all its manifestations, the health of one’s own and other people; environmental consciousness; nurturing love for nature;

Personal: understanding of responsibility for the quality of acquired knowledge; understanding the value of adequately assessing one’s own achievements and capabilities;

Cognitive: ability to analyze and evaluate the impact of environmental factors, risk factors on health, the consequences of human activities in ecosystems, the impact of one’s own actions on living organisms and ecosystems; focus on continuous development and self-development; the ability to work with various sources of information, transform it from one form to another, compare and analyze information, draw conclusions, prepare messages and presentations.

Regulatory: the ability to organize independent completion of tasks, evaluate the correctness of work, and reflect on one’s activities.

Communicative: formation communicative competence in communication and cooperation with peers, understanding the characteristics of gender socialization in adolescence, socially useful, educational and research, creative and other types of activities.

Technologies: Health conservation, problem-based, developmental education, group activities

Lesson structure:

Conversation - reasoning about previously acquired knowledge on a given topic,

Watching video material (film),

Subject «

« What determines the color of fish?”

Presentation "What determines the color of fish"

Sea creatures are among the most brightly colored creatures in the world. Such organisms, shimmering with all the colors of the rainbow, live in the sun-pierced waters of warm tropical seas.

Coloring of fish, its biological significance.

Coloration has important biological significance for fish. There are protective and warning colors. The protective coloration is intended to camouflage the fish against the background of the environment. Warning, or sematic, coloration usually consists of conspicuous large, contrasting spots or stripes with clear boundaries. It is intended, for example, for poisonous and poisonous fish, to prevent a predator from attacking them, and in this case it is called deterrent.

Identification coloring used to warn a rival in territorial fish, or to attract females to males, warning them that the males are ready to spawn. The last type of warning coloration is usually called the mating plumage of fish. Often the identifying coloration unmasks the fish. It is for this reason that in many fish that protect their territory or their offspring, the identification coloration in the form of a bright red spot is located on the belly, is demonstrated to the opponent if necessary and does not interfere with the camouflage of the fish when its belly is located towards the bottom. There is also pseudosematic coloration, which imitates the warning coloration of another species. It is also called mimicry. It allows harmless fish species to avoid the attack of a predator that mistakes them for dangerous look.

What determines the color of fish?

The color of fish can be surprisingly varied, but all possible shades of their color are due to the work of special cells called chromatophores. They are found in a specific layer of the fish's skin and contain several types of pigments. Chromatophores are divided into several types.

Firstly, these are melanophores containing a black pigment called melanin. Further, ethytrophores, containing red pigment, and xanthophores, in which it is yellow. The latter type is sometimes called lipophores because the carotenoids that make up the pigment in these cells are dissolved in lipids. Guanophores or iridocytes contain guanine, which gives fish a silvery color and a metallic sheen. The pigments contained in chromatophores differ chemically in stability, solubility in water, sensitivity to air and some other characteristics. The chromatophores themselves are also not the same in shape - they can be either star-shaped or round. Many colors in the coloration of fish are obtained by superimposing one chromatophore on another; this possibility is ensured by the occurrence of cells in the skin at different depths. For example, green color is obtained when deep-lying guanophores are combined with covering xanthophores and erythrophores. If you add melanophores, the fish's body turns blue.

The color of fish is quite important for their life.. The functions of coloring are divided into protective and warning. The first option is designed to camouflage the fish’s body in the environment, so this color usually consists of calm colors. Warning coloring, on the contrary, includes a large number of bright spots and contrasting colors. Its functions are different. In poisonous predators, who usually say with the brightness of their body: “Don’t come near me!”, it plays a deterrent role. Territorial fish, guarding their home, are brightly colored to warn rivals that the site is occupied and to attract a mate. A type of warning coloration is also the mating plumage of fish.

Depending on the habitat, the body color of the fish acquires characteristic features that make it possible to distinguish pelagic, bottom, thicket and school colors.

Thus, the color of fish depends on many factors, including habitat, lifestyle and diet, time of year and even the mood of the fish.

Identification coloring

In the waters teeming with all kinds of life forms around the coral reefs, each species of fish has its own identifying paint, like the uniform of football players of one team. This allows other fish and individuals of the same species to instantly recognize it.

The blenny's coloration becomes brighter as it seeks to attract a mate.

Dogfish is a deadly predator

The dogfish belongs to the order of rock-toothed or pufferfish, and there are more than ninety species of them. It is different from other fish unique ability bloat when frightened, swallowing large volumes of water or air. Then it pricks itself with its spines, releasing a nerve poison called tetrodotoxin, which is 1200 times more potent than potassium cyanide.

Dog-fish because special structure teeth was called rock-toothed. Fugu's teeth are very strong, fused together, and look like four plates. With their help, she splits shells of mollusks and shells of crabs, obtaining food. There is a rare case known when live fish, not wanting to be eaten, bit off the cook’s finger. Some types of fish are also capable of biting, but the main danger is their meat. In Japan, this exotic fish is called fugu; when skillfully prepared, it ranks first on the list of delicacies. local cuisine. The price for one serving of this dish reaches $750. When an amateur cook takes over its preparation, the tasting ends. fatal, since the skin and internal organs of this fish contain strong poison. First, the tip of the tongue goes numb, then the limbs, followed by convulsions and instant death. When gutting the fish, the dog emits a fetid, terrible odor.

The coloring of the Moorish Idol fish appears most vibrant when it is hunting its prey.

The main body color is white. The edge of the upper jaw is black. The lower jaw is almost completely black. In the upper part of the muzzle - bright orange spot with black edging. There is a wide black stripe between the first dorsal fin and the ventral fin. Two thin, curved bluish stripes extend from the first black stripe, from the beginning pelvic fins to the front of the dorsal fin, and from abdominal cavity to the base of the dorsal fin. The third, less noticeable, bluish stripe is located from the eyes towards the back. The second, gradually expanding, wide black stripe is located from the dorsal rays in the direction of the ventral ones. Behind the second wide black stripe there is a thin vertical white line. A bright yellow-orange spot with a thin white edge extends from the tail to the middle of the body, where it gradually merges with the main white color. The caudal fin is black with a white edge.

Daytime and night coloring

At night, the fusilier fish sleeps on seabed, taking on a dark color that matches the color depths of the sea and bottom. Waking up, it brightens and becomes completely light as it approaches the surface. By changing color, it becomes less noticeable.

Awake fish

Waking up fish

sleeping fish

Warning coloring

Seeing from afar brightly colored harlequin toothfish fish", other fish immediately understand that this hunting area is already occupied.

Warning coloring

The bright color warns the predator: beware, this creature has an unpleasant taste or is poisonous! Sharpnose pufferfish extremely poisonous, and other fish do not touch it. In Japan, this fish is considered edible, but when cutting it, an experienced expert must be present to remove the poison and make the meat harmless. Yet this fish, called fugu and considered a delicacy, claims the lives of many people every year. So, in 1963, 82 people were poisoned by viper fish meat and died.

The puffer fish is not at all scary in appearance: it is only the size of a palm, swims tail first, very slowly. Instead of scales - thin elastic skin, capable of swelling in case of danger to a size three times larger than the original - a kind of goggle-eyed, outwardly harmless ball.

However, the liver, skin, intestines, caviar, milk and even its eyes contain tetrodoxin - a strong nerve poison, 1 mg of which is lethal dose for a person. There is no effective antidote for it yet, although the poison itself, in microscopic doses, is used to prevent age-related diseases, as well as to treat prostate diseases.

Multicolor mystery

Most starfish move very slowly and live on clean day without hiding from enemies. Faded, muted tones would better help them become invisible, and it is very strange that the stars are so brightly colored.

Depending on the habitat, the color of the fish’s body acquires characteristic features that make it possible to distinguish pelagic, bottom, thicket and schooling colors.

Pelagic fish

The term "pelagic fish" comes from the location in which they live. This zone is the area of the sea or ocean which does not border the bottom surface. Pelageal - what is it? From Greek, “pelagial” is interpreted as “open sea”, which serves as a habitat for nekton, plankton and pleiston. Conventionally, the pelagic zone is divided into several layers: epipelagic - located at a depth of up to 200 meters; mesopelagic - at a depth of up to 1000 meters; bathypelagic - up to 4000 meters; over 4000 meters - abisopelagic.

Popular types

The main commercial fish catch is pelagics. It accounts for 65-75% of the total catch. Due to the large natural reserve and availability, pelagic fish are the most inexpensive type of seafood. However, this has no effect on taste qualities and usefulness. The leading position in the commercial catch is occupied by pelagic fish of the Black Sea, the North Sea, the Marmara Sea, the Baltic Sea, as well as the North Atlantic and Pacific seas. These include smelt (capelin), anchovy, herring, herring, horse mackerel, cod (blue whiting), and mackerel.

Bottom fish- most life cycle carried out at the bottom or in close proximity to the bottom. They are found both in coastal areas continental shelf, and in open ocean along the continental slope.

Bottom-dwelling fish can be divided into two main types: purely bottom-dwelling and benthopelagic, which rise above the bottom and swim in the water column. In addition to the flattened body shape, an adaptive feature of the structure of many bottom-dwelling fish is the lower mouth, which allows them to feed from the ground. Sand sucked in with food is usually expelled through the gill slits.

Overgrown color

Overgrown color- brownish, greenish or yellowish back and usually transverse stripes or streaks on the sides. This coloring is characteristic of fish from thickets or coral reefs. Sometimes these fish, especially in tropical zone, can be very brightly colored.

Examples of fish with thicket coloration include: common perch and pike - from freshwater forms; scorpionfish, many wrasses and coral fish are from the sea.

Vegetation, as an element of the landscape, is also important for adult fish. Many fish are specially adapted to life in thickets. They have a corresponding protective coloring. or a special body shape, reminiscent of the fish among which the fish lives. Thus, the long outgrowths of the fins of the rag-tailed seahorse, in combination with the appropriate coloring, make it completely invisible among the underwater thickets.

flocking color

A number of structural features, in particular the coloring of fish, are also associated with a schooling lifestyle. Schooling coloring helps fish orient themselves towards each other. In those fish in which a schooling lifestyle is characteristic only of juveniles, accordingly, a schooling coloration can appear.

A moving flock is different in shape from a stationary one, which is due to the provision of favorable hydrodynamic conditions for movement and orientation. The shape of a moving and stationary flock differs different types fish, nr can be different even in the same species. A moving fish forms a certain force field around its body. Therefore, when moving in a school, fish adapt to each other in a certain way. Schools are usually grouped from fish of similar sizes and similar biological conditions. Fish in a school, unlike many mammals and birds, apparently do not have a permanent leader, and they alternately focus on one or another of their members, or, more often, on several fish at once. Fish navigate in a school using, first of all, the organs of vision and the lateral line.

Mimicry

One type of adaptation is color change. Flat fish are masters of such a miracle: they can change color and its pattern in accordance with the pattern and color of the seabed

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Fish coloring

The coloring of fish is very diverse. The Far Eastern waters are inhabited by small (8–10 centimeters), smelt-like noodle fish with a colorless, completely transparent body: the insides are visible through the thin skin. Near seashore where the water foams so often, schools of this fish are invisible. The seagulls manage to enjoy the “noodles” only when the fish jump out and appear above the water. But the same whitish coastal waves that serve as protection for fish from birds often destroy them: on the shores you can sometimes see whole banks of noodle fish thrown up by the sea. There is an opinion that after the first spawning this fish dies. This phenomenon is typical for some fish. Nature is so merciless! The sea throws out both living and natural “noodles”.

Since noodle fish are usually found in large schools, they should have been used; Some of it is still being mined.

There are other fish with a transparent body, for example, deep-sea Baikal golomyanki, which we will talk about in more detail below.

On the far eastern tip of Asia, in the lakes of the Chukotka Peninsula, the black dallium fish is found.

Its length is up to 20 centimeters. The black color makes the fish inconspicuous. Dallia lives in dark-water peat rivers, lakes and swamps, and burrows into wet moss and grass for the winter. Externally, dalliya looks like common fish, but it differs from them in that its bones are delicate, thin, and some are completely absent (no infraorbital bones). But this fish has highly developed pectoral fins. Don't fins like scapulae help fish bury themselves in the soft bottom of a reservoir in order to survive the winter cold?

Brook trout are colored with black, blue and red spots of varying sizes. If you look closely, you will notice that the trout changes its attire: during the spawning period it is dressed in a particularly flowery “dress”, at other times – in more modest clothes.

The small minnow fish, which can be found in almost every cool stream and lake, has an unusually variegated color: the back is greenish, the sides are yellow with gold and silver reflections, the belly is red, yellowish fins have a dark edge. In a word, the minnow is small in stature, but it has a lot of force. Apparently, for this he was nicknamed “buffoon”, and this name is perhaps more fair than “minnow”, since the minnow is not naked at all, but has scales.

The most brightly colored fish are sea fish, especially tropical waters. Many of them can successfully compete with birds of paradise. Look at table 1. There are so many colors here! Red, ruby, turquoise, black velvet... They combine surprisingly harmoniously with each other. Figured, as if sharpened by skilled craftsmen, the fins and body of some fish are decorated with geometrically regular stripes.

In nature among corals and sea lilies these colorful fish present a fabulous picture. This is what he writes about tropical fish the famous Swiss scientist Keller in his book “The Life of the Sea”: “The fish of coral reefs present the most elegant spectacle. Their colors are not inferior in brightness and brilliance to the colors of tropical butterflies and birds. Azure, yellowish-green, velvety black and striped fish flickering and curling in whole crowds. You involuntarily take the net to break them, but... one blink of an eye - and they all disappear. With a laterally compressed body, they can easily penetrate the cracks and crevices of coral reefs.”

The well-known pike and perch have greenish stripes on their bodies that camouflage these predators in the grassy thickets of rivers and lakes and help them quietly approach their prey. But the hunted fish (bleak, roach, etc.) also have patronizing connotation: the white belly makes them almost invisible when viewed from below, the dark back is not noticeable when viewed from above.

Fishes living in upper layers water, have a more silvery color. Below 100–500 meters there are fish of red (sea bass), pink (liparis) and dark brown (lumpfish) colors. At depths exceeding 1000 meters, fish are predominantly dark in color (angler fish). In the area of ocean depths, more than 1700 meters, the color of fish is black, blue, purple.

Table 1. Fishes of tropical waters

The color of fish largely depends on the color of the water and bottom.

In clear waters, the bersh, which is usually gray in color, is distinguished by its whiteness. Against this background, the dark transverse stripes stand out especially sharply. In small swampy lakes, perch is black, and in rivers flowing from peat bogs, perch of blue and yellow colors are found.

Volkhov whitefish, which was once in large quantities lived in the Volkhov Bay and the Volkhov River, which flows through limestones, differs from all Ladoga whitefish in having light scales. According to it, this whitefish can be easily found in the general catch of whitefish in Ladoga. Among the whitefish northern half Lake Ladoga distinguishes black whitefish (in Finnish it is called “musta siika”, which means black whitefish).

The black color of the northern Ladoga whitefish, like the light one of the Volkhov whitefish, remains quite persistent: the black whitefish, once in southern Ladoga, does not lose its color. But over time, after many generations, the descendants of this whitefish, who remained to live in southern Ladoga, will lose their black coloring. Therefore, this feature may vary depending on the color of the water.

After low tide, the flounder remaining in the gray coastal mud is almost completely invisible: grey colour her back merges with the color of the mud. The flounder acquired this protective coloring not at the moment when it found itself on a dirty shore, but was inherited from its near and distant ancestors. But fish are capable of changing color very quickly. Place a minnow or other brightly colored fish in a black-bottomed aquarium, and after a while you will see that the color of the fish has faded.

There are many surprising things in the coloring of fish. Among the fish that live at depths where even a weak ray of sun cannot penetrate, there are brightly colored ones.

It also happens: in a school of fish with the usual color for a given species, there are individuals of white or black color; in the first case, so-called albinism is observed, in the second - melanism.

The coloration of fish, including the color pattern, is an important signal. The main function of color is to help members of the same species find and identify each other as potential sexual partners, rivals, or members of the same pack. Demonstration of a certain color may not go further than this.

Fish of certain species take on one color or another, demonstrating their readiness to spawn. The bright colors of the fins make a proper impression on potential sexual partners. Sometimes a mature female will develop a brightly colored area on her belly, emphasizing its rounded shape and indicating that it is filled with eggs. Fish that have specific bright spawning colors may appear dull and inconspicuous when not participating in spawning. A conspicuous appearance makes the fish more vulnerable to predators, and predatory fish unmasks.

Spawning coloration may also serve as a stimulus for competition, for example in the fight for a spawning partner or for spawning territory. Preservation of such coloration after the end of spawning would be completely pointless, and perhaps even clearly unprofitable for schooling fish.

Some fish have an even more highly developed color language, and they can use it, for example, to demonstrate their status in a group of fish of the same species: the brighter and more provocative the color and pattern, the higher the status. They may also use coloration to show threat ( bright color) or submission (dull or less bright color), and this is often accompanied by gestures and body language of fish.

Some fish that show parental care for their offspring have a special coloration when they guard the young. This guard coloring is used to warn uninvited guests or attract attention to yourself, distracting from the fry. Scientific experiments have shown that parents use certain types colors to attract fry (to make it easier for them to find their parents). Even more remarkable is that some fish, using body and fin movements, as well as coloration, give various instructions to the fry, for example: “Swim here!”, “Follow me” or “Hide at the bottom!”

It should be assumed that each species of fish has its own “language” corresponding to its special way of life. However, there is clear evidence that closely related fish species clearly understand each other's basic signals, although they most likely have no idea what representatives of the other fish family are “talking” to each other. By the way, the zoo portal jokingly sorted the fish by color:

The aquarist cannot “answer” the fish in their language, but in Sioah he can recognize some of the signals given by the fish. This will make it possible to predict the actions of underwater inhabitants, for example, to notice an approaching spawning or a growing conflict.

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