The Number – Cypriniformes
Family – Priniv
The genus/Species – Serrasalmus nattereri
Length: average 20 cm, in some species up to 50 cm.
Mass rarely exceeding 1.5 kg.
Caviar: a few thousand eggs.
The incubation period is 10-15 days, depending on water temperature.
Habits: constant float huge flocks.
Food: primarily fish; attack mammals, floating or come to the waterhole, and birds.
18 known species of piranhas, 4 of which are dangerous to humans, although fatal cases have been identified. Continue reading
Hundreds of thousands of years ago, long before the appearance on Earth of man, the oceans already swam fish. At that time they were the most highly developed creatures.
Since then, they began to develop a variety of ways so that now only some species only vaguely resemble the first primitive ocean fishes.
As a rule, fish has an elongated and tapering shape. People have copied it in the construction of ships and submarines, as it is the best adapted to movement in water.
Most fish use their tail as a motor. With the help of fins and they control their movements. Except for one species of fish, all the others breathe by means of gills. Fish swallows mouth water that passes through the gills and out through the hole. Water also contains oxygen, and it through the gills into the blood of fish, as the air through the lungs in the blood of man. Continue reading
In the Atlantic ocean, the Black sea and off the coast of India dwells amazing and a bit scary fish monkfish .With it is associated a very curious phenomenon. For a long time researchers could not understand why all the water harvested from fish of this species are invariably females. As they multiplied.
Only after the beginning of the heavy deep-sea studies have found out that monkfish has developed a unique mechanism of reproduction. It turned out that the male and female fish monkfish differ in size a thousand times. The female is a large part of his life spent in the coastal zone and can grow up to two meters long, and the male also reaches only a few centimeters and lives at great depths, where is the justice in this world = ( . This was established when he was discovered living at depths of more than two hundred meters tiny fish acerated. Caught deep-sea dredges of acaracide were always males. Only after painstaking research revealed that acerated is (many readers probably already guessed it) a male sea devil, and not a separate species or a subspecies.
To find such a small male helped another feature of the sea devil — the annual migration of huge females on the depth taken by them for the purpose of procreation. Continue reading