Piranhas are monsters from horror films and scary stories, small but bloodthirsty inhabitants of the waters of the Amazon and other rivers in South America (Colombia, Venezuela, Paraguay, Brazil, Argentina). What do we know about them? Perhaps nothing. After all, all knowledge is limited to only one kind - the usual piranha, which has earned itself a notoriety.
What does a piranha fish look like?
The Piranha family has a little over 60 species of fish. And, oddly enough, most of them are herbivores, they practically do not eat animal food. The size of the piranhas depends on the species, carnivores generally reach 30 cm, and their vegetarian relatives can gain significant weight and grow more than one meter in length. Coloring also depends on the species, but mostly silver-gray, and becomes darker with age. The body shape is diamond-shaped and high, compressed laterally. The main food for predators is a variety of freshwater fish, piranhas can feed on animals or even birds that meet on the way. For herbivorous species, the Amazon and its tributaries abound in various vegetation, do not disdain these fish and nuts, seeds that fall into the water.
Jaw structure
The piranha is characterized by the amazing structure of the jaw apparatus, which, perhaps, has no analogues in nature. Everything is provided in it to the smallest details. Teeth having a triangular shape and sizes of 4-5 mm, lamellar and sharp, like a razor blade, are slightly bent inward. This allows them to easily cut the flesh of the victim, tearing pieces of meat. In addition, the upper and lower teeth ideally fit into the sinuses when closing the jaw, creating strong pressure. This feature allows piranhas to bite bones. When closed, the jaw closes like a trap. According to recent research by scientists, the power of a bite is 320 Newtons and has no analogues in the animal kingdom. The jaws of a piranha exert a pressure that is about 30 times its weight when bitten.
Where do piranhas live?
These are the inhabitants of freshwater in South America. The Amazon basin contains a fifth of all fresh water, this river is full of diverse fish. Piranhas live along the entire length of the river and are the subject of many legends and stories of local residents. The floodplain of the river occupies vast territories, most of it belongs to Brazil, but besides this, Ecuador, Colombia, Bolivia and Peru. Piranhas also feel great in other rivers, the area of their habitat in the territory of the South American continent is very large.
Recently, this fish has become very popular in home keeping and breeding. The piranha in the aquarium will grow smaller than the size that is typical for it in natural conditions, and slightly loses its aggressiveness. Surprisingly, with such a menacing appearance, they become fearful in a confined space and often hide in artificial shelters.
All piranha fish are united in one family and are divided, according to the zoological classification, into three subfamilies.
Myelina Subfamily
Myelins are the largest group, it unites seven genera and 32 species. These are herbivorous and absolutely harmless piranhas (photo). Fish eat plant foods. Coloring is quite diverse, depending on the species. The body shape is characteristic, laterally compressed and high. In young individuals, the color is silver-steel, with varying degrees of spotting, which darkens to a chocolate-gray color as it grows. Sizes range from 10 to 20 centimeters. Many representatives of this subfamily are bred in aquariums. They need a large amount of water and enough space for shelter, as this is a rather shy fish. Aquarium piranha from the myelin subfamily will feel good at a water temperature of 23-28 degrees, and the daily diet should include salad, cabbage, spinach, peas and other vegetables. Some species even eat nuts in natural conditions, easily cracking a strong shell with their powerful jaw.
Black Paku - the brightest representative of myelin
Black pacu (or the Amazonian broadbody) is the most famous representative of the Myelina subfamily. In addition, it is also the largest: its sizes range from 30 centimeters to one meter or more, while at the same time it is not a predator. The coloring of adult individuals is quite modest, brownish brown, but the young growth has a silver color with a large number of spots throughout the body and bright fins. Black Paku meat has good taste and is used by locals. These are fishing piranhas. Aquarium conditions are also quite suitable for them, but the size of the fish will be slightly smaller than in nature, on average about 30 centimeters, life expectancy - within 10 years or a little more. The maintenance of this species requires a large aquarium (from 200 liters) and good care.
Subfamily Catoprionins
This subfamily is represented by only one species - these are flag piranhas. The fish are quite harmless and lead a semi-parasitic lifestyle, their main food is the scales of other fish, although the appearance of these aquatic inhabitants is quite ominous, and they are not inferior in severity to their carnivorous counterparts. The shape of the flag piranha is diamond-shaped, flattened laterally. The color of the scales is gray-green with a silver sheen. A distinctive feature is the presence of a red speck on the gill covers. The extreme rays of the anal and dorsal fin are very elongated, while the caudal fin has a black root . The dimensions are small, only 10-15 cm.
This fish, similar to common piranha and being its closest relative, in its main diet (60%) has plant foods, and only 40% are small fish. But you still need to keep it separate from other fish, otherwise the very small ones will be eaten, and the large ones risk being left with damaged fins and partially without scales. As an animal feed, you can use small shrimp or fish, earthworms, and vegetable - spinach, lettuce, nettle and other greens.
Subfamily Serrasalmins
These are the very ruthless predators, the subfamily is represented by only one genus and 25 species. All of them eat animal food: fish, animals, birds. The size of the piranhas of the Serrasalmin subfamily can reach sizes up to 80 cm, reaching a weight of up to 1 kg. This is a real threat to animals (not to mention fish), which in size can exceed them several times, but this does not stop piranha. The appearance of small predators is really formidable: the lower jaw protrudes significantly and is slightly bent up, the eyes are convex, a rounded flat body shape is characteristic. In ponds, they prefer to keep in packs, but when attacking a victim, they act independently of each other, therefore it cannot be said that these are close-knit group fish. Piranhas react to movement in the water, this attracts their attention. When one of them finds a victim, the rest instantly flies to the place. Moreover, there is an opinion of zoologists that piranhas are capable of making sounds, thereby transmitting information to each other. A pack of piranhas can leave only bones from the animal in a few minutes.
The information that they are able to feel the blood at a decent distance from the victim is true. Piranha fish live in the muddy waters of the Amazon, and it is natural that they had to adapt to poor visibility conditions, as a result - a well-developed sense of smell. Piranha really draws blood, this is a signal of the appearance of the victim.
In addition, they do not disdain carrion and even their sick or weakened brothers. For animals and humans, only a few species pose a real danger.
Common piranha
The most famous representative around whom conversations do not cease is the Common Piranha. The length of an individual of this species can reach up to 30 centimeters, but basically they are the size of a person’s palm. Ordinary piranhas (photo of the fish below) have a greenish-silver color with many dark spots throughout the body, on the abdomen the scales have a characteristic pinkish tinge. They live in packs of approximately one hundred individuals.
In recent years, ordinary piranhas have been very popular in home maintenance. Aquarium conditions help to reduce aggressiveness. But the aquarium still needs a separate one.
Black piranha
This is another species from the Serrasalmina subfamily, very common in nature and popular in home breeding. The habitat is the Amazon River and the Orinoco. The body shape is diamond-shaped, and the color is dark, black and silver. In young fish, the abdomen has a yellow tint. Black piranha is an omnivorous predator, everything fits into the diet: fish, arthropods, birds or animals accidentally caught in water. Such illegibility in food led to their rather high abundance in the waters of the Amazon. Although the aggressiveness of the species is inferior to the same ordinary piranha. Aquarium for such fish needs a large, more than 300 liters. The difficulty of breeding is the aggressiveness of piranhas in relation to each other. Reproduction is possible if the aquarium representatives of the family eat properly, with an abundance of animal food, they are obese, which can become a significant obstacle to the appearance of offspring. In the photo - black piranha.
Myth one: piranhas attack a person
It is definitely difficult to judge this, since the data are very contradictory. Many scientists and zoologists who spent more than one year on the Amazon have never witnessed an attack, in addition, they themselves, endangering themselves for the sake of experiment, bathed in the muddy waters of the river, where they caught piranhas a few minutes before, but didn’t attack followed.
For a long time, there was a rumor about a bus with local residents who drove into one of the tributaries of the Amazon, and all passengers were literally eaten by piranhas. The story really took place in the 70s of the last century, 39 passengers died, but one managed to escape. According to eyewitnesses, the bodies of the victims were really badly damaged by piranhas. But to judge whether this attack was and whether it was the cause of death is not possible.
There are reliable sources of bites on the beaches of Argentina when the first to attack fish. But these were isolated cases. Zoologists attribute this to the fact that piranhas, the spawning of which just begins at the height of the beach season, build nests in shallow water. Therefore, this behavior of fish is quite natural: they defended their offspring.
In addition, piranhas are most dangerous for humans and animals during a drought, when the water level in the rivers reaches its minimum, which affects their diet: there is less food. Local residents know about this and do not enter the river at this time. The safest season is the rainy season when the rivers flood.
Myth two: piranhas attack in packs
There are a lot of stories about the terrible attacks of an entire flock, all this is fueled by numerous feature films. In fact, large individuals do not prowl in search of prey in the river, they stand in one place, usually in shallow water. The fish is waiting for its prey, and as soon as this prey appears, the piranha goes to the right place. Attracted by the noise and smell of blood, the rest rush there. Piranhas gather in packs not for hunting prey, but for defense against the enemy - as many scientists believe. It would seem, who can harm them? However, even such a predatory fish has enemies. Piranha, gathering in packs, defends itself against the river dolphins that feed on them, and for humans they are harmless and quite friendly. In addition, among the natural enemies of piranhas are arapaim and caimans. The first is a giant fish, which is considered almost a living fossil. With its amazing, heavy-duty scales, it poses a real threat to piranha. Fishes occurring alone, instantly become a victim of arapaima. Caimans are small representatives of the Crocodile squad. Zoologists noticed that as the number of these caimans decreases, the number of piranhas in the river immediately increases.
Myth three: piranhas appear in the reservoirs of Russia
Incidents really took place to be, but this is the result of either the behavior of sloppy aquarium fish lovers, or an intentional launch into a pond. In any case, concern is in vain. Although piranhas adapt perfectly to any conditions, the main factor for their successful existence remains the same - a warm climate and water (within 24-27 degrees), which is impossible in our country.
Of course, these are predatory fish. Piranhas are dangerous and very voracious, but nevertheless stories about them are often too embellished and made up. The indigenous population of South America learned to coexist alongside piranhas and even made them an object of fishing. Nature has not created anything useless: if wolves are the orderlies of the forest, then piranhas perform a similar function in water bodies.