Interesting facts from the life of fish. The most interesting facts about fish. The most interesting facts from the life of the underwater world

• Most fish lay eggs to reproduce, but there are several species of fish that give birth to ready-made fry. This is, for example, a great white shark.
• The mudskipper is a fish that spends most of its time out of water and can “walk” on its own fins. Jumpers store a small supply of water in their gills for a long time. They can also breathe through the pores of their moist skin.
• The stingray has more than 27,000 taste buds. Compared to him, a person has almost four times less of them - “only” 7,000.
• Most brands of lipstick contain substances that are part of fish scales. They give lipstick a unique shine.
• Lungfish can live out of water for several years. It secretes a slimy protective coating and, in dry years, burrows into the clay, sucking in air through a built-in breathing tube that emerges to the surface. Lungfish have both lungs and gills.
• Seahorses are the only fish species that can swim upright.
• Some fish, such as the white shark, can raise their own body temperature to hunt in cold water.
• Pisces use low-pitched sounds to convey messages to each other. They moan, growl, wheeze, mumble, hiss, whistle, squeak and squeal. They crack their bones and grind their teeth. However, fish do not have vocal cords. They use other parts of the body to produce sound, such as vibrating muscles located opposite the swim bladder.
• Schools of fish can reach several million in number. They use their eyes and what is called a lateral line to orient their body in the pack. The lateral line consists of a series of pores that run through the fish's body from the head to the tip of the tail. Special hairs in the pores sense changes in water fluctuations produced by their relatives or predators.
• Electric eels and stingrays can kill a horse with their electric shocks.
• The only species of fish that have eyelids are sharks.
• Some fish, such as herbivorous fish, often lack teeth in their jaws, but have tooth-like "mills" in their throats called pharyngeal teeth.
• Fish can change sex due to water pollution. Around one third of fish in British waters have changed sex due to pollution caused by sewage systems.
• The oldest fish hook found was made about 42,000 years ago.
• Most sea fish have unsalted flesh, but there are sharks whose flesh is as salty as the ocean in which they live.
• Most fish distinguish colors and use them for camouflage or to protect their territory. Some fish can see polarized and ultraviolet rays.
• The age of a fish can be determined by the growth rings on its scales. Over the years, the number of fish scales does not increase; they grow in size along with the fish.
• The ship's keel is located at the bottom and protects it from capsizing. On the other hand, the fish has its keel at the top. If the twin fins stop working to maintain balance, the fish will turn belly up as the heavier side tends to move downwards. This is exactly what happens to dead fish.
• On average, a flying fish can glide for 50 meters, but cases have been recorded of individual specimens hovering 200 meters above the water. When flying, these fish can reach a height of up to 6 meters.
• The fish can... drown. Like humans, fish require oxygen to maintain life. If there is little oxygen dissolved in the water, the fish will simply suffocate.
• Most fish species do not have a “reverse gear”. Only some representatives of the eel order can swim tail first.
• The largest fish in the world is the giant whale shark, which can grow up to 18 meters, which is roughly the length of two school buses. It can weigh up to 25 tons and feeds on plankton. The whale shark has more than 4 thousand teeth, although their length is only 3 millimeters.
• The most poisonous fish in the world is the wartfish or stonefish. The bite of this sea monster causes shock, paralysis and even death if action is not taken within the first few hours after poisoning.
• The word "piranha" comes from the language of the Tupi Indians living in Brazil (sounds "pira nya"), which means "scissors". This fish, living in the fresh water of the rivers of South America, has razor-sharp teeth. Piranhas typically feed on fish, insects, seeds, plant fruits, and even animals such as horses. Although there is no evidence that they kill people, they do eat human corpses.
• The fastest fish is the sailfish. She can swim at the speed of a car moving along a highway.
• The slowest fish are seahorses, which move so slowly that, looking at them from the outside, one can say that they are at rest. The slowest of them is considered to be the dwarf seahorse, which covers a distance of 1.5 meters in one hour.
• Some fish have no scales. For example, a shark has skin as rough as sandpaper.
• In Japan, fugu fish is an exceptional but deadly delicacy. It contains tetrodoxin, which is a deadly poison. However, fugu is so delicious that Japanese gourmets risk their lives to cook it. To serve such a dish, a Japanese chef must have a certificate from a special school where they teach the art of preparing this poisonous fish.
• A male imperial angelfish has up to five females in his harem. If the “head of the family” dies, then one of the females turns into a male and takes the place of its predecessor.

The report on cartilaginous fish will briefly tell you about these inhabitants of the oceans and seas. A report on cartilaginous fish will help you prepare for class and deepen your knowledge in the field of biology.

Report on cartilaginous fish

Cartilaginous fish inhabit seas and oceans. They are characterized by a completely cartilaginous skeleton, which consists of the skull and vertebral column. The vertebral bodies are biconcave. Between them there are gaps where the remains of the chord are located. They are also present in the vertebral bodies.

The upper cartilaginous arches of the vertebrae end in the spinous processes. They form a canal with the spinal cord. The brain of cartilaginous fish is protected by the brain case. The lower vertebral arches in the caudal region form a canal that protects the dorsal aorta. The body is covered with placoid scales.

Their internal structure is characterized by the absence of a swim bladder. In order not to fall to the bottom of the reservoir, cartilaginous fish must be in constant motion. The circulatory system of fish supplies the organs with blood much more efficiently than that of other fish species. In the heart of animals there is an arterial cone, due to which the efficiency of blood circulation increases. The brain is better developed than in bony fishes due to the enlargement of the forebrain. Representatives of the class of cartilaginous fish have a cloaca, which is an expanded final section of the intestine. The ducts of the reproductive and excretory systems flow into it.

What do cartilaginous fish eat?

Cartilaginous fish feed on other small fish, mollusks and crustaceans.

How do cartilaginous fish reproduce?

Cartilaginous fish reproduce in several ways: oviparity, ovoviviparity, or viviparity. They are characterized by internal fertilization and direct development.

The meaning of cartilaginous fish

Cartilaginous fish are very important to oceanic and marine ecosystems. They are valuable commercial species for humans. Fish skin is used in the leather industry. Medicines are made from shark liver tissue. They are also used in cooking to prepare exotic dishes from fins or other parts of the body of fish. By processing fish tissues, industrial fat and meat and bone meal are produced. Many species are kept by humans in aquariums as pets.

Interesting facts about cartilaginous fish:

• Cartilaginous fish have universal immunity. After millions of years of evolution, they have become resistant to all diseases.
• Some fish breathe not only through their gills, but also through their skin.
• Shortly before the birth of their offspring, cartilaginous fish lose their appetite so that predators do not eat their own offspring.
• They have excellent hearing and can hear their prey 300 m away.
• Almost all cartilaginous creatures see the world in a black and white spectrum. And only sharks can blink synchronously.

We hope that the report on cartilaginous fish helped you prepare for the lesson. You can supplement the story about cartilaginous fish using the comment form below.

Along with invertebrates, amphibians, reptiles, birds and mammals, fish are one of the 6 main groups of animals, and are widely distributed in oceans, seas, lakes and rivers around the world. In this article, you'll discover 10 basic facts about fish, ranging from how these aquatic vertebrates breathe to their reproductive habits.

1. There are three classes of fish

Fish are divided into the following three main classes:

1) Ray-finned fish (Actinopterygii)- the most diverse class, including more than 20,000 species of fish known to science;

2) Lobe-finned fish (Sarcopterygii)- class to which the genus of ancient fish - coelacanths - belongs;

3) (Chondrichthyes)- a class that includes such well-known fish as sharks and rays, as well as chimeras.

2. All fish have gills

Like all animals, fish need oxygen to maintain their metabolism: the difference is that land animals breathe air, while fish get oxygen from water. To this end, fish have developed specially adapted gills - complex, efficient, multi-layered organs that absorb oxygen from the water and release carbon dioxide. For the gills to function normally, it is necessary that oxygenated water constantly pass through them; for this reason, fish are in motion most of the time and quickly die if they are out of water.

Some species of fish (for example, lungfish), in addition to gills, have rudimentary lungs, and are able to breathe air when circumstances require it.

3. Fish were the first vertebrates on the planet

Before the appearance of “true” vertebrates, there were small marine animals with bilateral symmetry, as well as a primitive nervous system running along the length of their body. A little over 500 million years ago, during the Cambrian period, a population of chordates evolved into the first true vertebrates, providing the foundation for the reptiles, birds, amphibians and mammals we all know and love.

The most numerous of them, invertebrates, have followed their own evolutionary path and today they make up a whopping 97 percent of all fauna species.

4. Most fish are cold-blooded

Like reptiles, to which fish are distantly related, the vast majority of fish species are cold-blooded: they depend on the temperature of the environment (water) to maintain their internal metabolism. However, barracudas, tuna, mackerel and swordfish - all belonging to the suborder mackerel - have a warm-blooded metabolism, although it is quite different from that of mammals and birds. Tuna can maintain a core body temperature of 32 degrees Celsius, even when swimming in 7 degree Celsius water!

Mako sharks are also warm-blooded, which gives them extra energy when chasing prey.

5. Fish are oviparous, not viviparous.

Unlike other vertebrates, most species of fish fertilize their eggs (eggs) externally: the female lays hundreds or thousands of small, unfertilized eggs, and the male at this moment releases his sperm into the water, thereby fertilizing the eggs. Some fish are characterized by males using their penis to transfer sperm into the female.) There are exceptions: ovoviviparous fish, the fry of which emerge from eggs in the female’s body, as well as viviparous fish, for example, the lemon shark, which has an organ very similar to the placenta of mammals.

6. Most fish have a swim bladder

Fish live in stratified ecosystems: 10 meters below the water surface is very different than at a depth of 1-2 kilometers. For this reason, it is in the fish's best interest to maintain a constant depth, which most species achieve using the swim bladder, a gas-filled organ that keeps the fish buoyant and eliminates the need to swim at top speed.

7. It's possible that fish can feel pain.

Even people who advocate more humane treatment of "higher" vertebrates such as cows and chickens are tight-lipped when it comes to fish. But there are some controversial studies suggesting that fish can feel pain, even though they lack the brain structure associated with pain like mammals. In England, the Royal Humane Society passed a resolution against cruelty to fish, which supposedly applies more to mutilations from fishhooks than to industrial fish farms.

8. Pisces are unable to blink

One of the anatomical features that makes the fish a little strange is the lack of eyelids, and therefore their inability to blink: the mackerel's gaze will remain the same glassy, ​​regardless of the relaxed or anxious state of the fish. In this regard, the logical question arises, does the fish sleep? Despite their constantly open eyes, there is some evidence that fish do sleep, or at least tend to sleep. restorative behavior similar to human sleep: some fish slow down their swimming pace, and also hide under stones, in corals and algae.

Even when the fish are completely motionless, underwater currents still supply the gills with vital oxygen.

9. The lateral line replaces hearing and smell in fish

Many fish have excellent eyesight, but their hearing and sense of smell leave much to be desired. However, these marine animals have a sensory organ, the lateral line, which is absent in terrestrial vertebrates. The lateral line is located along the entire length of the body and detects water vibrations, and in some species, even electrical impulses. This organ is especially important for maintaining a place in the food chain: predators use the lateral line to track prey, and prey, in turn, to avoid encounters with predators.

Fish also use their lateral lines to form schools and choose the right direction during migration.

10. Commercial fish stocks are declining at a catastrophic rate.

The world's oceans are so vast and teeming with life that people could be forgiven for thinking that tuna, salmon and other game fish are an inexhaustible source of food. In fact, overfishing can easily lead to the extinction of many fish populations as people consume more seafood than they can replenish.

Unfortunately, despite the real risk of losing valuable species, industrial fishing for some fish species continues. If trends continue, some of our favorite fish could disappear from the world's oceans within 50 years.

Fish belong to a group of aquatic animals that have a backbone and gills for breathing. They are found almost everywhere: in salt and fresh water bodies, in fast mountain rivers and small streams, in the mysterious depths of the ocean and small swamps, they also feel good in home aquariums. People are accustomed to seeing fish dishes on their table; almost everyone knows about their health benefits. They are grown on an industrial scale on their own farms and small ponds.

Professional fishermen and amateurs regularly organize fishing competitions. And they completely forgot about how amazing and diverse the world of fish is. What fantastic survival devices has nature come up with?


Do you know how many species of fish are known to scientists? It’s hard to even imagine such a figure - approximately 33 thousand, and this is not the limit; about 500 completely new ones are identified and described every year. In Russia alone lives approximately 3 thousand varieties. An entire science, ichthyology, is engaged in their study and classification.

There are hermaphrodite fish in the world that can breathe oxygen from the air, move long distances on land and above the surface of the water, swim at the speed of a car, give birth to live young, and not reproduce by caviar, as we used to think.


Marine inhabitants belonging to the class of fish play the role of orderlies and have talents for healing. They can run, jump, and shoot down insects from plants located near a pond with a stream of water. They take care of their offspring no worse than people. Some of them are so brightly colored that you just can’t take your eyes off them, just right for organizing beauty contests.

The most interesting facts from the life of the underwater world

• Exist hermaphrodite fish(groupers, wrasses, taxa, etc.) are endowed with the ability to change sex, this occurs as a result of environmental influences or the needs of the population. A very intelligent adaptation for the survival of the species. The male of the clan died, the eldest of the women takes his place, gradually turning into a male individual. The history of the family continues.
• There are fish that have gills and lungs. This feature helps to survive during periods of drought. Burying deep into the clay, they breathe through a breathing tube that goes to the surface. The body is protected from drying out by special mucus.
• One species of fish has eyelids. These are sharks, known to everyone as the most bloodthirsty sea predators.
• Electric rays and eels can kill a horse with the current they produce.
• The most popular (branded) lipsticks are made using special substances that give a special shine, isolated from the scales. It turns out that in cosmetology you simply cannot do without the class of fish.
• A stingray has about 27 thousand receptors, while a person has only 7. It would make an excellent taster.
• Fish are viviparous. Among them are the great white shark and the well-known aquarium favorite, the gupia. By the way, it also lives in natural reservoirs of Brazil, Venezuela, and Guiana.
• The mudskipper can go without water for a long time because there is a water supply in the gills for a long time. Also, representatives of this species are able to breathe through the pores on the skin.
• Fish do not have vocal cords. They communicate using their entire body (crackling bones, holding teeth together). They have special vibrating muscles near the swim bladder, and it is with their help that they produce moaning, wheezing, gurgling, whistling, grinding and even squealing.
• Almost all species distinguish colors and even use them for camouflage and territory defense.
• The scales have growth rings that can be used to determine age. Scales do not change with age, but increase in size.
• The flying fish easily flies 50 meters, but there are also record holders up to 200 meters, the flight altitude above the water is 6 meters.
• The fish is constantly swimming, but strangely enough, it can drown. This happens when there is little oxygen in the water, which is vital for all living beings; without it, they suffocate and go to the bottom.
• The largest fish has grown to 18 meters in length and gained 25 tons in weight, while it constantly feeds on plankton. This is a whale shark.
• Piranha - translated as “scissors”, lives in the fresh water of South Africa. Eats fish, various seeds and fruits, insects and animals. She can even handle a horse, but killing people has not yet been proven, although they eat corpses, thus being a water orderly.

Considered the most poisonous stone fish. After the bite, shock and paralysis begin, and if help is not provided after a couple of hours, death may occur. In the competition of the slowest, the dwarf seahorse wins at a speed of one and a half meters per hour. Looking at him, one gets the impression of floating in one place.


The fastest fish - sailboat. It moves like a car on a highway.

And the sea is knee-deep for the fish

At great ocean depths, fish are known intoxication effect, but not from alcohol, as is common among people, but from the high content of carbon dioxide. In this case, coordination is lost and the feeling of fear is completely eliminated. Their nerve cells are constantly in a state of increased excitability. The reason for the phenomenon is an increase in the acidity of water, caused by the high content of carbonic acid in it, which is produced by the interaction of carbon dioxide and sea water.

First aid from fish

In the waters rich in useful minerals, near the Turkish city of Sivas, there lives an amazing doctor fish. She gnaws off dead skin scales, actively participating in the treatment of people suffering from psoriasis and other dermatological problems. She does this very delicately, without injuring healthy skin.

The world of waterfowl amazes with its beauty and diversity. Despite the progress, deep sea trenches remain unexplored, and who can guess what amazing discoveries await us in the future. How many new fish, amazing in their abilities, will be discovered by our science.

The biggest fish in the world- a giant whale shark that can grow to almost 18 meters in length. It weighs more than 25 tons and feeds mainly on plankton. She has more than 4,000 teeth, although they are only 3 mm long.

The most poisonous fish in the world- Wartfish (Synanceia verrucosa) or stone fish. Its bite can cause shock, paralysis and even death if not treated within a few hours. The poison is also contained in the thorns, which can be easily stepped on, since they imitate stones very well. It measures 35–50 centimeters and lives mostly in the southern seas and oceans. The most favorite habitat of this fish is the seabed near coral reefs. Be careful while diving!

Fastest fish- a sailboat that lives in the Indian Ocean, as well as in the western and central parts of the Pacific Ocean. It can swim as fast as a car drives on a smooth highway. The speed of this fish was measured in the USA. It was 109-110 km/h! However, there is information according to which the fastest fish in the world is another fish. Swordfish can reach speeds of up to 130 km/h. She is very aggressive and is not afraid to attack even large ships.

Slowest fish- sea Horse. She swims so slowly that it may seem to a person that he is standing still. A seahorse takes about 1 hour to swim 1.5 meters. The seahorse is the only type of fish that swims while in an upright position.

Most seahorse species mate for life. Female pipits lay their eggs in a pouch on the male's belly. When the children are ready to leave, the male holds onto a sheet of seaweed or stones with his tail and swings until the fry jump out of the bag.

The seahorse can move each of its eyes separately. One eye can look forward, while the other can look back at the same time. Seahorses are also capable of changing their color to match their surroundings.

Catfish have over 27,000 taste buds (more than any other animal).

While Black Sea perches are young, they are mostly female, but at the age of 5 years, many individuals will change their sex to male.

Humpback whales make the loudest sound of any living creature.

Sharks, one of the largest species of fish, do not have bones in their body. Their skeleton is made of cartilage (flexible bones, like humans have in their ears and nose). The shark's skeleton can be easily crushed on land by its own weight. Sharks and rays are the only animals known to man that do not get cancer. Scientists believe that this has something to do with the fact that they do not have bones, but only cartilage.

Some fish do not have scales. Sharks, for example, have rough, sandy skin.

Most fish have brackish muscle tissue. Sharks have tissues that are saturated with salt, just like the ocean in which they live.

The shark is the only fish that has eyelids.

A shark can detect one particle of blood in 100 million parts of water.

Some sharks replace more than 30,000 teeth in their lifetime.

The oldest known goldfish lived to be 41 years old. Her name was Fred.

Most fish reproduce by spawning, although some fish, such as great white sharks, give birth to live baby sharks called pups.

Although the saberfish is only a few inches long, it has teeth comparable in size to human teeth.

The mudskipper is a fish that spends most of its time out of water and can "walk" on its fins. She carries a portable source of water in her gill chambers. She can also breathe through the pores of her wet skin.

Women's lipsticks add fish scales to achieve a shimmering effect, which is why most lipsticks contain fish scales.

The Australian lungfish can live out of water for several years. It secretes mucus and lubricates itself under the unbaked earth. She breathes air with the help of her lungs, through a built-in breathing tube that is brought to the surface. It has both gills and lungs. It is also the oldest known fish species in terms of age. In 2003, she was still alive and was 65 years old.

Some fish species, such as the great white shark, can increase their body temperature. This helps them hunt for prey in cold water.

Pisces use low-frequency sounds to convey messages to each other. They moan, grunt, croak, hiss, whistle, squeak and even howl. They rattle their bones and grind their teeth. However, fish do not have vocal cords. They use other parts of the body to make noises, such as vibrating muscles located behind the swim bladder.

Fish are capable of forming schools containing up to several million fish. They use their eyes and what is called a lateral line to position themselves in the school. The lateral line of pores is located along the sides of the fish from head to tail. Special hairs in the pores sense changes in water pressure from the movement of other fish or predators.

Because a fish's jaw is not attached to its skull, many fish can move their mouths forward to catch prey.

Electric eels and electric rays have enough electricity to kill a horse.

Pisces have sleep-like periods when they reduce their response to stimuli, physical activity and metabolism, but these are not the same changes in the brain that occur in humans when they sleep.

Some species of fish, such as herbivorous fish (herbivores), often do not have jaw teeth, but they do have tooth-like mills in their throats called pharyngeal teeth.

Most fish have taste buds throughout their bodies.

Water pollution can change the sex of fish. It is estimated that one third of male fish in British waters change their sex due to wastewater from factories and cities.

Saltwater fish need more water to drink than freshwater fish. Since sea water is salty, part of the fluid in the fish's body constantly flows out of it through osmosis. If they did not drink to renew the lost water, the sea fish would dry out like a prune.

The oldest fish hook ever found by archaeologists is 42,000 years old.

Most fish are able to see color and use colors to camouflage or protect themselves and their territory. Most fish have the best vision for their environment. Some fish species can see polarized and ultraviolet light.

The age of a fish can be determined by the size of its scales. The fish does not add new scales while it is growing, but it does increase in size. Thus, the scales show the age of the fish.

Fish that have thin fins with a slit tail indicate that they move very quickly and can swim long distances. Fish that live among rocks and reefs near the ocean floor have wide lateral fins and large tails.

The ship has a heavy keel at the bottom to prevent capsizing. Fish have a keel on top. If the paired fins stop working to keep the fish balanced, the fish will capsize because the heavier part tends to sink, which is what happens when it dies.

On average, flying fish can glide through water 50 m, but there is evidence that they can glide 200 meters. They can jump up to 6 meters in height.

The porcupine fish can reach a diameter of up to 90 cm. It inflates itself by swallowing water and then stores it in its stomach. The stomach quickly increases in size. If the fish is removed from the water, it may similarly gulp air.

Fish can also drown in water. Like people, fish need oxygen, so if there is not enough oxygen in the water, they suffocate.

Most fish cannot swim backwards. Those that can do this mostly belong to one of the eel families.

The word "piranha" comes from the name of the Tupi tribe (Brazil) "Pira nya" and means "scissors". Found in the freshwater rivers of South America, piranhas have razor-sharp teeth. They typically eat fish, insects, seeds, fruits, and even larger animals such as horses. After a piranha feast, only the skeleton of the victim remains. Piranhas are capable of eating their relatives if they are too hungry or if they are bleeding.

Pisces are mentioned in Christian and pre-Christian sources. For example, the Greek word "Ichthys", meaning fish, is an abbreviation for "Jesus Christ, Son of God, Savior" and was used to refer to early Christian tombs and meeting places of early Christians. Because of their close connection with fertility, fish were also previously associated in people's beliefs with the goddesses Isis and Aphrodite.

In Japanese, "fugu" literally means "river pig". In Japan, fugu fish is a succulent but deadly delicacy. It contains tetrodotoxin, which is a deadly poison to humans. However, na is so delicious to the Japanese that Japanese gourmets risk their lives to taste it. To make this high-risk dish, chefs must have a certificate from a special school that specifically teaches them how to prepare this toxic fish.

The hammerhead is a shark that lives in schools of more than 500 sharks at once. The strongest swim in the middle. When the male is ready to mate, he shakes his head from side to side, attracting females.

Some desert needlefish are able to live in hot springs, where the water reaches temperatures above 45°C.

Male emperor angel fish live together with five females at once. If the emperor dies, one of the females turns into a male and becomes the leader of the group.

There are approximately 32,000 different species of fish in the world, which is more than all other vertebrate species combined. Scientists are constantly discovering more and more new species of fish.

The batfish pretends to be dead when it senses danger nearby. He floats motionless on his side when she is scared, making himself look like a dry leaf floating on the surface of the water.

Anableps - a fish with four eyes can simultaneously see above and below the water level.

Sometimes a tornado captures schools of fish while moving through the water and dumps them on the ground as rain. These "fish rains" have been happening for thousands of years. The Roman writer Pliny the Younger described this phenomenon in the 1st century AD.

99% of the ocean depths remain unexplored. Scientists have explored only 1% of all ocean depths. They believe that millions of new species of animals and fish are there, waiting to be discovered.

Empty fish eggs sometimes wash up on the beach. Some people call them mermaid wallets.

A salmon, after traveling across the ocean, can find the river where it was born. Salmon are also adapted to life in a variety of aquatic environments, including rivers, lakes, estuaries, coal reefs and the open sea.

Fish were the first bony vertebrates to appear on Earth. Unlike modern fish, ancient fish did not have scales, fins or jaws, but they did have a dorsal fin.

Hagfish are one of the slimiest animals on earth. An Atlantic hagfish can make enough mucus in one minute to fill a bucket. Unlike bony fish, sharks and rays, they do not have a swim bladder. They must swim all the time, even when they are sleeping. Otherwise, they will settle to the bottom of the ocean.

Unlike most other ocean fish, the sunfish does not have a tail. A female sunfish can lay 300 million eggs a year.

The freshwater pygmy fish and Luzon gobies of the Philippines, the sea goby of the Marshall Islands, and the tiny rice fish of Thailand have a maximum length of about the size of a grain of rice. They are generally considered to be the world's smallest fish.

It turns out that fish have the ability to count. This fact was repeatedly confirmed by a group of Italian scientists. Thus, Christian Agrillo, one of the employees of the University of Padua, who participated in the experiment, said: “We would have received evidence that fish are endowed with rudimentary mathematical abilities.”

Before these experiments, it was already known that fish have the ability to find the difference between small and large schools of fish, but the experience of Italian scientists showed that fish are also able to count the number of fish that swim around them. Other species of animals are endowed with similar mathematical abilities: dolphins and monkeys.

The Italians' experience consisted of observing the behavior of females of a freshwater fish species - gambusia. Studies have shown that if a male mosquitofish is hunting a female, she will try to hide from him in the largest nearby school of fish.