Poisonous fish. Descriptions, features and names of poisonous fish

Environmentalists opposed plans for mass breeding of Poecilia reticulata (guppies) fish in South American countries, but they can be bought here in online stores or regular stores in the city https://lysmata.ru, reports Science magazine.

The article states that such plans are being hatched by the authorities of a number of South American countries. They want to introduce guppies en masse into water bodies to combat the Zika fever epidemic.

It is believed that the virus is carried by mosquitoes, the larvae of which are eaten by these fish. However, environmentalists opposed the idea. They presented their arguments in an article published in the scientific journal Biology Letters, Rossiyskaya Gazeta writes.

Scientists refer to studies conducted. They showed that once in a foreign body of water, guppies begin to actively reproduce. In competition, they displace local fish species and change the chemical composition of the water. Where large populations of these fish live, the level of dissolved nitrogen in the water increases and stimulates the rapid proliferation of algae.

Laboratory tests have also shown that guppies will only feed on mosquito larvae as a last resort. In experiments, they fast for a very long time before switching to such a diet. According to environmentalists, guppies will not bring significant benefits in the fight against fever, but will disrupt the biobalance.

Let us add that guppies are one of the most popular fish among aquarists, as they are quite unpretentious. In the wild they live in the reservoirs of Venezuela, Guiana, Brazil, the Caribbean islands, as well as a number of countries in Africa and Southeast Asia.

The most dangerous aquarium fish

Cube body

And don’t let this cute name and cute appearance of the fish fool you. Behind all this lies a real fiend of hell! It's all about the toxic mucus that the box releases during times of danger. The poison will easily kill all the inhabitants of the aquarium, including the cube itself. This self-sacrifice can be explained by the fact that the fish is not used to living in the confined space of an aquarium, and it is difficult for it to calculate the portion of poison.
The size of an adult individual reaches up to 60 cm. They live in tropical waters in shallow waters and at depths of up to 50 meters. They eat what Poseidon sent them, prefer fresh meat and algae.

Piranha is one of the most dangerous fish

When compiling a list, it would be a sin not to mention piranhas, glorified in myths and legends. We all remember horror films well, where small fish caused a lot of problems. But are piranhas really that dangerous? Let's put it this way: for humans, no, for small animals it is, although if you put your finger in the mouth of a fish, it can stay there forever. They attack mainly carrion, but they will not disdain a chick that has fallen from the nest.
If you place predators in an aquarium, its other small inhabitants will soon be exterminated, and the piranhas will not be greedy, they will exterminate methodically, one fish a day, and will bite off the fins of everyone else so that the prey does not swim far.
The size of an adult piranha is only 20 cm. There are up to 30 species. They live in South America. Piranhas are very angry and aggressive fish. Hardly anyone would be happy to be around them.

Pufferfish

This is a very poisonous fish. They are considered an exquisite delicacy in Japan and are called “Fugu Fish”. But how can something that is more poisonous than cyanide be tasty? The secret is simple - they need to be cooked correctly, but this does not eliminate poisoning; dozens of people become victims of the delicacy every year. This species also has the peculiarity of inflating at the slightest danger, so that it is difficult for predators to swallow them.
Pufferfish feed on protein; shellfish and squid are used. They reach sizes of 40-50 centimeters. They require good water for a comfortable existence.

Triggerfish

These fish are suitable for experienced aquarists. They have powerful jaws lined with teeth and are capable of biting a wire or even the finger of a curious guest. They treat neighbors calmly, but if a quarrel arises, they will bite to death without a second thought. The character of fish, as a rule, is bad. They have a very strong immune system and live long and happy lives without disease.
Size up to 50 cm. They feed on everything, and it is better to feed them from a distance, otherwise they can bite very painfully.

Electric eel

There are many types of eels that can be placed in aquariums. Some of them are armed with sharp spines, the other part with teeth, the electric eel produces a current of up to 600 volts! Eels are not friends with their neighbors, even if they are of the same species. Therefore, one eel - one aquarium.
The fish eats the protein. It grows in an aquarium up to 100-150 cm. Most of the time the eel is at the bottom, but leaves it when it senses food. A very dangerous and whimsical fish. Caring for her is not something everyone can do!

Decorative aquariums are a wonderful sight: lush green thickets, lovely bustle and always unique design. But you shouldn’t give up once again on some of the hungry inhabitants of such beauties.

Freshwater aquarium keeping

Sacbranch catfish

A very interesting and incredibly dangerous fish, which, moreover, can breathe atmospheric air. In nature, there have been cases when, having exterminated the fry in their habitat, catfish crawled to the shore, where they fed on insects and frogs. In an aquarium they behave more calmly, but when they smell food, they will not hesitate to take it even from the mouth of another fish. They have sharp, poisonous spines on their dorsal and pectoral fins, the sting of which resembles a bee sting. Therefore, people suffering from allergies need to be especially careful in their contents.

Tetradon

He has a very grumpy character and can only get along with large, active neighbors. The fish's ability to inflate has earned it the nickname "little airship." But dwarf tetradons deserve special attention from the aquarist; they are among the smallest predators on earth and grow up to only 4 cm.

Acantophthalmus

Watching a small, fairly calm predator, it’s hard to even imagine what danger it poses in nature to its enemies. If such a worm fish is inadvertently grabbed by a larger predator, it will immediately arm itself with sharp spikes, which are located under each eye, and will pierce the walls of its stomach, and sometimes even come out.

It would seem that what could be more harmless than an aquarium? An almost hermetically sealed container, no hair or dirt in the apartment, and bacteria from the water are unlikely to spread throughout the house. So what harm can an aquarium cause to humans? Some doctors believe that it is quite serious.

In a sensational program at one time, the famous Elena Malysheva spoke about the following horrors that await careless aquarists:

Salmonellosis, which can be contracted from fish and through aquarium water. This disease is very unpleasant and extremely dangerous for young children and people with weakened immune systems.

Aquarium granuloma, or fish tuberculosis. The cause is bacteria from the genus Mycobacterium. Koch's bacillus, which causes human tuberculosis, belongs to the same genus.

Allergy to fish food. According to doctors, it is strictly forbidden to have an aquarium in a house where there are people with allergies.

In order to protect yourself and your family from these misfortunes, it is proposed to disinfect the aquarium and all its equipment and contents (fortunately, except for fish) weekly with special means - in the worst case, boil it.

For hygienic purposes, only sufficiently large pebbles that are easy to wash are allowed as soil, and plants - for the same reasons - are exclusively plastic.

It is clear that by complying with such sanitary requirements, we will very quickly kill all the fish. And in conditions of imbalance of microflora and hydrochemical indicators it is impossible to achieve: dregs, then, and then an unpleasant odor will appear all the time.

How seriously should we take doctors’ warnings and what can be done to safely care for your home pond without violating the principles of aquarium biology?

The first horror: salmonellosis

This is where respected doctors are wrong. Fish do not spread salmonellosis. But reptiles - snakes, lizards, turtles, including popular ones - can themselves suffer from salmonellosis or be carriers of this disease.

They excrete bacteria with excrement, so you can become infected from a reptile through close contact (when the animal is often picked up or allowed to crawl on the dining table) or when cleaning the terrarium and not following hygiene rules.

Therefore, when keeping these animals, you should adhere to the following rules:

• wash your hands after handling the reptile or cleaning the terrarium (aquaterrarium);

• do not allow the reptile or terrarium care items to come into contact with human utensils or food;

• create optimal living conditions for animals, since carrier animals in poor conditions and under stress release much larger amounts of bacteria into the external environment.

The second horror: aquarium granuloma, or fish tuberculosis (pseudotuberculosis)

This is the only zoonosis (disease transmitted from animal to human) that aquarium fish can suffer from. Moreover, this disease is very widespread and its causative agents - mycobacteria - are present in almost every aquarium. However, it only affects weakened fish that live in cramped conditions, dirty water, or with a lack or poor quality of food.

This disease is treated with antibiotics. Some experienced aquarists recommend holding your hands over a warm heating pad or lamp as a treatment, since the fish bacterium does not tolerate heat.

Avoiding granulosis is very simple: do not put your hands in the aquarium when there are wounds or inflammations on them, and if this is necessary, then you should do this with long veterinary gloves. And, of course, it is important not to forget to wash your hands after handling the aquarium.

The third horror: food allergy

Indeed, fish food such as dried daphnia and gammarus often cause allergies: they crumble into fine dust, and this dust, consisting of tiny particles of chitin, is very dangerous for allergy sufferers. But what is the need in the 21st century to feed fish with dried daphnia?

There are a lot of modern dry food, including granulated or made in the form of tablets, which do not crumble or create dust.

And besides them, fish can also be fed with live food, including those grown independently and therefore clean and safe, minced fish and seafood, omelettes, vegetable mixtures and much more.

In short, there is no need to breathe chitin dust.

It turns out that what doctors scare us with is not so scary, it is not at all necessary to get sick from an aquarium, and there is also no need to carry out endless disinfection procedures that harm animals. It is enough to follow simple and understandable hygiene rules.

Frozen bloodworms are a nutritious food for fish, sold in many pet stores.

What can really be dangerous in an aquarium?

The biggest danger is electric current

When combined with aquarium water, it can cause trouble. Therefore, several rules should be followed:

• electrical equipment must be placed in such a way that water cannot get into the sockets;

• the entire electrical network must be fully operational;

• Do not touch plugs and sockets with wet hands; it is recommended to keep a towel near the aquarium and develop the habit of wiping your hands with it before touching electrics;

• You must first turn off all the aquarium equipment, and only then put your hands in the water (an exception can only be made for an external canister filter).

The second real danger is large predatory fish

They don't always agree to pretend to be cute pets. The severum or astronotus guarding the clutch can bite quite strongly, and the zebra lionfish, a decoration for marine aquariums, can be pricked by a poisonous spine. So you need to be careful.

And one more thing that requires careful handling is aquarium chemicals: conditioners, medicines for fish, liquid carbon and fertilizers for plants. When using them, you must take precautions and be sure to keep them away from children. Poisoning with these drugs can be much more dangerous than the mythical fish tuberculosis.

In general, be careful when caring for your aquarium, follow simple and obvious rules, and no harm will come from it. Or maybe the doctors are right after all, and aquarists are really too careless?

Video from the “Live Healthy” program about the dangers of an aquarium, which caused a resonance among aquarists (48th minute):

; ; ; ; ;
Read the essay:"Sea ruff" - scorpionfish; ;
* Scorpionfish, or sea ruffe and others
*Fugu is the most poisonous but edible! ; ; ; ; ;

POISONOUS FISH (sharks and rays)

Currently, two classes of fish are distinguished: the class of cartilaginous fish (Chondrichthyes), numbering about 630 species, and the class of bony fish (Osteichthyes), uniting over 20,000 species. Among cartilaginous and bony fish there are species that are more or less dangerous to humans. Poisonous representatives of cartilaginous fish are stingrays and some sharks. Among the poisonous bony fish are sea bass (Sebastes), European stargazer (Uranoscopus scaber), large dragon (Trachinus draco), marinka (Schizothorax) and some other inhabitants of our waters.

Poisonous fish can be divided into actively and passively poisonous. Constant presence in such a specific habitat as water left its mark on the formation of protective devices, including poisonous ones. Mucous glands, characteristic of aquatic organisms, provide not only an improvement in the hydrodynamic characteristics of the body, but also perform protective functions. Various thorns and thorns, often equipped with specialized poisonous glands, originating from the mucous glands of the skin, serve the same purpose. The combination of a wounding device with a gland in the poisonous apparatus, which produces a poisonous secretion, can be observed in stingrays, scorpionfish and other fish. This is an example of a perfect form of an armed poisonous apparatus, which can be conditionally classified as “personal means of chemical protection.”

Another type of protection - supraorganismal, population - is associated with the localization of toxins mainly in the internal organs of the body, especially in the genitals. It is no coincidence that the concentration of toxins in such fish is maximum during the spawning period, which can be interpreted as an adaptation aimed at maintaining the population size. An example of this can be the representatives of the family. Carp species (Cyprinidae), which have poisonous reproductive products (marinka, osman, etc.).

Fish are one of the essential sources of food for humans, so the study of their poisonous representatives is of great economic importance.

Actively poisonous fish

Common spiny shark, or katran - Squalus acanthias L.

Class Cartilaginous fish - Chondrichthyes Order Katraniformes - Squaliformes Family Spiny sharks - Squalidae

Ecology and biology. A medium-sized shark, about 1 m long. It is colored gray-green, darker on top. Both dorsal fins bear one sharp, prickly spine. Common in the Black Sea, it is also found in the Barents and White Seas, where it is known as nokotnitsa (or marigold). Numerous in the Far Eastern seas. In coastal waters it leads a school life, descends to a depth of 180-200 m. It feeds on fish, crustaceans, and cephalopods. Ovoviviparous. It is dangerous only in direct contact - if taken in hand, it can cause deep wounds with poisonous thorns.

The structure of the poisonous apparatus. The top of the spine is bare, but the lower part is covered with a leathery sheath, under which poisonous glands are located. They are strands of large polygonal cells, the cytoplasm of which is filled with small granules. When immersed in the body of the victim, the gland cells are compressed, and the poisonous secretion pours out.

Picture of poisoning. There is fragmentary information about the lesions inflicted by the katran. Local phenomena are of leading importance: tissue damage, pain, hyperemia, swelling. Possible wound infection.

Treatment is symptomatic.

Chemical composition and mechanism of action of the poison. The active principle is protein in nature. The poison is thermolabile and is destroyed by organic solvents, acids, alkalis, and UV irradiation. In experimental animals in toxic doses it causes paresis and paralysis of skeletal muscles.

Practical significance. Commercial species.

Stingrays

Class Cartilaginous fish - Chondrichthyes Order Stingrays, or Diamond-bodied rays - Rajiformes Family Stingrays, or Stingrays - Dasyatidae

Ecology and biology. In the Black and Azov Seas there is a sea cat (Dasyatis pastinaca L.), usually reaching a length of 1 m. The color is grayish-brown, without spots (Fig. 49). The tail is long and whip-shaped. In the middle part of the tail there is a jagged spike on both sides. The much larger giant stingray, Urolophoides giganteus, is occasionally found in Peter the Great Bay in the Far East. The total length of its body reaches 2.3 m. The tail is short, thick, armed with two long jagged spines. Typically, stingrays lie at the bottom, partially buried in sandy or muddy soil. They feed on fish and crustaceans.

The structure of the poisonous apparatus. Venom glands are located in the grooves of the ventral surface of the spines. The spines of large species can reach significant sizes - up to 30 cm. With strong impacts, they often break off, the fragment is firmly held in the tissues of the victim, thanks to the notches directed back. The glands do not have special ducts; the secretion accumulates in the grooves of the spine. At the moment of impact, under pressure from the victim’s tissues, a secretion is released near the spear-shaped tip of the spike. Venom-forming cells have a system of microtubules surrounded by a common membrane. On a cross section inside the oval formed by a closed membrane, up to 5000 microtubules can be counted, the average diameter of which is 20 nm. It is assumed that these microtubules contain a toxic secretion.

Picture of poisoning. Most often, fishermen, scuba divers and swimmers suffer from stingray injections. It is useful to remember that the force of the tail of large stingrays is such that they can easily pierce clothing and shoes. However, stingrays almost never use their spine to attack: human injuries are usually the result of careless handling of fish or an accident (Fig. 51). Usually, after being pricked by a stingray thorn, the victim experiences acute burning pain and hyperemia of the affected area. The pain radiates along the lymphatic vessels. Later, swelling develops, sometimes spreading over a considerable distance. Poisoning is characterized by the development of weakness, sometimes with loss of consciousness, diarrhea, convulsions, and breathing problems. In humans and experimental animals, stingray venom causes a drop in blood pressure and disruption of heart function. If the limbs are affected, recovery may occur within a few days. However, a shot in the chest or stomach can be fatal. Treatment is symptomatic.

The active principle of the poison is apparently represented by a thermolabile protein, the physicochemical and toxic properties of which have not been sufficiently studied.

Practical significance. The sea cat, as well as the Far Eastern red stingray Dasyatis akajei, are commercial species. ...

The brown rocktooth, or brown puffer, or brown dog-fish, or ocellated dog-fish, or northern dog-fish (lat. Takifugu rubripes) is a species of marine ray-finned fish from the family of pufferfish of the order pufferfish. Even though it is considered a delicacy in Japan and is very expensive, the average tourist should be very careful when encountering it. When pricked with its needle, the fish releases poison - tetrodotoxin, which can kill a person, because an antidote for it has not yet been found. It is found both on the skin and in the internal organs, so cooking fugu yourself is strictly prohibited. The fish reaches a length of 50 cm and is found at a depth of about 100 meters. Distributed in the south of the Sea of ​​Okhotsk (northern coast of Hokkaido Island), in the western waters of the Japanese Sea (along the mainland coast from Busan to Olga Bay; along the island from the southwestern coast of the island of Honshu to southwestern Sakhalin), the Yellow and East China Seas, along the Pacific coast of Japan from the Volcanic Bay to the island of Kyushu. In the Russian waters of the Sea of ​​Japan, where it enters north of Peter the Great Bay and up to South Sakhalin, it is common in the summer.
Fugu fish contains a lethal dose of tetrodotoxin in its internal organs, mainly the liver and caviar, gall bladder and skin. The liver and caviar of puffer fish should not be eaten at all; other parts of the body should not be eaten after careful special processing. The poison reversibly (can be metabolized) blocks sodium channels in the membranes of nerve cells, paralyzes muscles and causes respiratory arrest. Currently, there is no antidote; the only way to save a poisoned person is to artificially maintain the functioning of the respiratory and circulatory systems until the effect of the poison wears off. Despite the licensing of fugu cooks, every year a number of people who eat incorrectly prepared food die from poisoning. Currently, it is possible to produce poison-free fugu fish on a large scale. Research has shown that fugu fish is not capable of producing neurotoxin, but only accumulates it in its body. Tetrodotoxin is initially produced by marine bacteria, which are then eaten by a variety of living organisms.
Eating improperly prepared fugu can be life-threatening. Therefore, to prepare fugu in special restaurants, since 1958, Japanese chefs have had to undergo special training and obtain a license. In the past, there was a tradition in Japan according to which, in case of fugu fish poisoning, the cook who prepared the dish had to also eat it (or commit ritual suicide).
For a long period in Japan, it was forbidden to eat fugu and there was even a ban on catching fugu fish. Similar bans are now in effect in some countries in Southeast Asia, however, they are not always effective. So, despite the ban on fugu fish in Thailand since 2002, it can still be purchased in local markets.