Fish and other aquatic creatures

Fish hedgehog - a spiny deadly ball

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However, almost half a thousand people - this is not enough. Scientists have long been looking for ways to scare away sharks. In 1937, the beaches of Sydney at night were fenced with fixed nets. After that, in the fenced areas, there was not a single shark attack on a person. Moreover, the number of these predators caught in the net at night was decreasing from year to year — whether sharks in the seas became less and less, or they learned to recognize danger.

In 1952, networks as a defense against sharks began to be used in Durban (South Africa) with the same success - not a single attack on bathers. However, this method has a significant drawback - harmless animals are dying in the nets, over which the threat of extinction hangs: dolphins, sea turtles, etc.

The shark has very sensitive sensors that capture the weak currents and sound vibrations, as well as odors. This feature of predators is used to create various repellents (repellers). A weak electromagnetic field that is safe for other marine life and humans can stop a shark and keep it away from the radiator.

American scientists have developed a device Shark Shield ("Shark Shield"). It can be attached to a boat, surfboard or compressed air bottle. The generated electromagnetic radiation, according to the developers, is able to keep the shark at a distance of several meters.

The sound emitter is similarly arranged. The shark perceives low sound and infrasound. High frequencies cause her discomfort. It is assumed that the ultrasound generator will scare the predator. However, tests of all types of emitters have shown that there is no universal repellent: one that scares a shark of one type is ignored by another.

Chemical protection against these formidable fish is also being developed. It is noticed that sharks are trying to stay away from decaying corpses of their relatives. Scientists have synthesized a substance that mimics the carcass shark smell. Experimental tests have shown a certain effectiveness of this tool.

Tip 3: What types of sharks are considered the largest

Not so long ago, the largest of the sharks was considered by zoologists to be the great white shark, the carcharodon (Carcharodon carcharias). She to this day is such among the famous predatory sharks. The average length of the sample is 5-6 m, and the usual weight is 600-3200 kg. The largest of this species reached 11 m. There is an assumption that larger specimens can also be found.

An even larger species of shark and the largest fish currently known in the world is the whale shark (Rhincodon). Its usual dimensions reach 10-14 meters. There are also giant specimens in 18 m.

In 1990, scientific information appeared on a specimen of a whale shark with a size of 20 m and a weight of 34 tons, which is approximately the weight of an average sperm whale! This fact in modern sources is indicated as verified.

The whale shark is a very small species. Unlike the relative, the great white shark, it is not dangerous and feeds on plankton, draining it from the water. She is not aggressive and behaves peacefully. Some researchers of the underwater world even managed to touch it.

The whale shark swims quite slowly, cruising near the surface of the water at an average speed of 5 km / h. For a long time this type of shark was unknown. For the first time, scientists managed to get to know him in 1828, when sailors mined 4.5-meter fish.

Hedgehog fish description

Most often, these fish have an average length - 30 centimeters, but as much as possible they can reach 90 centimeters. The whole body is studded with spikes, up to 5 centimeters.

The color of most individuals is light, but dark spots are scattered throughout the body. The head is dull, round shape.

Fish hedgehog armed with powerful jaws that look like a beak.

Inside the beak are not teeth, but sharp plates. With the help of its fish beak, the hedgehog is able to crack shellfish and corals.

Spikes are modified scales that can be mobile in some species and rigid in other species. The fins are small and weak; therefore, against the current, these fish cannot swim fast. But, despite the slowness, fish hedgehogs can stop and swim in all directions.

Hedgehogs (Diodontidae).

Varieties of fish hedgehogs

In total, there are about 15 species of hedgehog fish, combined in 6 or 8 genera, for example:
• Doubles,
• Allomiktery,
• American chylomict
• Spotted chilomic,
• Yellow spotted cyclicht
• Avian cyclicht,
• Spotted Dicotilt,
• Dikotilikhty,
• Long-eared hedgehog fish,
• Pelagic fish hedgehog,
• Long-eared hedgehog fish,
• Lofodions,
• Short-haired fish hedgehog,
• Traguliht,
• Lofodion.

The family of hedgehog fish has up to 8 genera, common in almost all tropical seas.

Hedgehog fish lifestyle

These fish live alone, keeping close to the corals. A small slow fish seems to be easy prey, but a predator that is trying to swallow this fish will die. Often come across dead sharks and barracudas, the last meal of which are fish hedgehogs. They get stuck in the throat of their victim, causing her to die. A predator who has swallowed a hedgehog fish dies a painful death from numerous wounds to the esophagus.

All these species of hedgehog fish are typical inhabitants of coral reefs. This is not too excellent swimmers. When the fish hedgehog falls in during or ebb, it can bring to the shores of northern Europe.

Since fish, hedgehogs swim slowly, they cannot flee from the enemy, so they developed their weapons of self-defense.

The body size of the fish increases many times in just a few seconds. From a small fish, it turns into a ball the size of a soccer ball, which is covered with sharp spikes, 5 centimeters long. The hedgehog fish spikes resemble porcupine quills. It is dangerous for predators not only for its thorns, there is also a strong poison in its skin and liver.

The diet of fish hedgehogs

Fish hedgehogs eat corals. Of the hard limestone skeletons of coral reefs are formed, they are very strong, but, from the teeth of fish hedgehogs, they are not able to protect themselves.

The fish bites off a piece of coral and crushes it with sharp plate, performing the function of teeth.

The remains of limestone accumulate in the stomachs of fish hedgehogs in the form of powder, which eventually leaves the body. Once a hedgehog fish was found, in the stomach of which there was 0.5 kilogram of coral powder. In addition to coral fish, hedgehogs eat oysters and mollusks.

These fish are only interested in the edible parts of the polyps.

Breeding fish hedgehogs

These fish excrete gametes into the environment. Scientists know very little about the breeding of hedgehog fish. It is assumed that the breeding method of them is the same as that of their close relatives - fish of puffer fish. Females throw a large amount of caviar into the water, and males - milk.

Caviar is fertilized, and quite mature fry leave it. Merging and development of eggs is carried out arbitrarily. Fry appear from the surviving eggs, they are copies of adult individuals, even immediately able to swell.

Fish hedgehogs hunt at night, in connection with which they have very sharp eyesight.

Interesting fish hedgehogs

• The spikes are heavily modified scales, which form a protective chainmail on the body of the fish,
• Residents of one island in the Pacific Ocean made military helmets from dried fish bodies of hedgehogs
• Fish in hedgehogs in some countries are eaten, they are considered a delicacy. But they can be eaten only after they undergo a special culinary treatment. But such a delicacy can be very dangerous. If an inexperienced cook cooks a fish for a hedgehog, it can be poisonous,
• In the Far East, dried fish are sold to hedgehogs or products made from their skin, for example, lampshades. Also, Chinese lanterns are made from dried fish in a bloated state.

Preserving the species of fish hedgehogs

These fish are not considered a popular object of fishing, most often they are harvested to create souvenirs for tourists. And in Japan, these dangerous fish are served. But fish hedgehogs are a common species, and they do not need protection.

Ballfish (Tetraodon palembangensis)

The detachment of fish in question, includes mainly the family of marine fish, but it also includes the family of freshwater (Tetraodontidae) and those who live in saline bodies of water. The latter has several genera, the most numerous of which are Tetraodon. In turn, this genus is represented by 23 species of fish, of which all are freshwater, except for one.

Tetraodon natural habitat is a reservoir of two continents: Asian and African. Representatives of various genera of Tatraodonts in Asian countries are represented in the waters of China, India, Thailand, the Malay Peninsula, Indonesia, Malaysia, Bangladesh, Sri Lanka, and Myanmar. In Africa, the fish live in the basins of the Nile River. Congo, Niger, Volta, in Lake Chad, Tanganyika, Tana and smaller lakes.

Some species of Asian tetraodon prefer rocky soils and rapid currents, others - the smooth course of canals and rivers or standing ponds. But those and others love shady vegetation, muddy water. As food they are mollusks, crustaceans, insects and their larvae, worms, aquatic plants.

African fellow chose to live mostly large rivers and lakes with abundant vegetation. They are found on the rapid current and on the thresholds. These fish are skilled hunters. The subject of their hunt is mainly fish, in which tetraodons attack from below. The basis of their food is crustaceans, mollusks, insects that have chitinous shell (fish grind their teeth about him, as they grow very quickly).

The sizes of theraodonts of different types range from 8 to 70 cm.

Each tetraodone species has an aquarium with special conditions.

Be prepared for the fact that not all representatives of tetraodons are created the same living conditions in a home aquarium. They are different depending on the species of these fish. And aquariums should differ not only in their design, but also in the content of fish-balls in it. In this context, it makes sense to divide tetraodons into three groups.

Group №1 - Tetraodon leniatus

For its representatives, prepare a low aquarium with walls no higher than 35 cm. But with a large bottom area. Put a mixture of sand (fine and medium) of uniform color without dark inclusions on the bottom. Place the stones on top so that they give the fish an easy access between them. Build caves of stones, which will serve tetraodons asylum.

Representatives of this group are the most aggressive and of nature can be described as predators waiting for their prey in ambush. In the cave you set up they will give their prey. Keep in mind that they are not capable of getting along with other fish: they eat small ones, get rid of large ones, mortally injuring them.

Be sure to equip the aquarium with a pump to improve water circulation and a powerful internal filter. The optimum temperature for tetraodons of this group is 24-26ºС, the permissible pH range is 6.5-7.5, water hardness (dH) is 5-10. degrees

The specificity of the nutritional diet of tetraodons from this group is such that they require live fish or fish pieces with bones. The need for bones is due to the fact that fish grind their fast-growing teeth about them.

Group number 2 - Tetraodon turgidus, biocellatus, cochinchinensis, cutcutia, palembangensis

Its representatives will require an aquarium of 100-150 liters. Pour a mixture of dark (medium and coarse) sand on the bottom. Build caves of stones and place in the capacity of the snag. Planting plants is risky, because the fish can simply destroy them. If there are several fish in the aquarium, then a separate cave will be needed for each. It is better if the theotraodones are alone in the aquarium. Other fish for them - just food.

The diet of this group should consist of gastropods. shrimp, mussels, pieces of fish.

To create a current in the aquarium that this group likes so much, place a pump and a medium filter in the water. The favorable temperature of the content is 24-28 ° C with a pH balance of 6-8 and a hardness of 5-10.

Group 3 - large African tetraodons (mbu, lineatus)

In view of the large size of the fish in this group need large aquariums. Their capacity must be at least 500 liters. Cover the bottom with coarse sand of dark colors. Whether to plant plants - decide for yourself, because the risk that they will be eaten is always there. It is better to plant a bamboo - its tetraodons are definitely not touched. Plant bamboo stalks in such a way that between them there is a space in which the fish could swim freely.

Keep in mind that adult individuals are characterized by aggression, so solitary content is the best option for them. But "youth" is distinguished by peacefulness and gets along well with each other.

Food of fish of this group - pieces of fish with bones, clams, shrimps. Large mollusks sometimes have to visit a tetraodon aquarium and live.

Create a moderate flow rate in the aquarium using a compressor and a medium-sized internal filter.

Comfortable for Tatraodons of this group is the water temperature of 24-26ºС. The optimum pH is 6-7, dH - 5-15.

Proper conditions of detention contributes to the long life of large African tetraodons - 10 years or more.

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