We all know that water is life. Without water can’t live no living creature. And the first life originated in water. Fish one of the many live organisms living in the aquatic environment. They live in the oceans and seas, rivers and lakes. You can see them in the pond and the stream, in the waters of caves and even in puddles. In nature, there are over 25,000 species of fish, and they are divided into two classes: Bony fish (more than 23 000 species); Cartilaginous fishes (9000 species).
To the class of cartilaginous fish include sharks, rays and chimeras. To the class of bony fish include salmon. okuneobraznyh. preobrazenie. clupeiformes. Cypriniformes, catfishes, wildcookie, flatfish, coloscopie.
Fish are cold blooded vertebrates. their streamlined body covered with scales. They breathe with gills, and with the help of fins and tail to swim. Water entering the body through the mouth, passes through the gills, and spilling over her holes. Oxygen enters the bloodstream Continue reading
Thus, the spawning period is defined more clearly than most tropical species, for which the importance is not so much the temperature, the amount of rainfall.
You can determine the start time of spawning, regularly measuring the temperature of the water in the pond, because the spawning usually begins at a temperature of about 20°C. At this temperature the eggs develop normally. Plus or minus 5 °C, and the fry will be deformed, because things will develop too quickly or too slowly.
Physical changes in the fish also indicate the approach of spawning. For example, the males of the family Cyprinidae appear white swellings, called tubercles. Fish such as Orfe, Rudd, goldfish and koi, the tubercles appearing on the Gill covers and pectoral fins, while Cipriani – along the scalp.
Some fishes, such as sticklebacks, coloring of the male becomes brighter, attracting mates and scaring off rivals. Females of all cold-water species become fuller males. Continue reading
Jellyfish, sea anemones, coral polyps, annelid worms, sea cucumbers, sea urchins, starfish, sponges can “burn” or stabbing of a person in contact with them. The range of consequences — from burning the skin before the heart stops.
The most venomous jellyfish is the sea wasp, lives off the coast of Australia. The venom of this beautiful jellyfish paralyzes the heart muscle, death occurs within 1-3 minutes. It seems to be a normal jellyfish light green in color but very poisonous. Its 60 tentacles, each a little less than 40 cm long, has 5,000 flowing down the stings and venom enough to kill 60 people. Australian fishermen, in whose nets such “fish”, beware to use these networks again – you can easily go to the hospital, so strong poison secreted by jellyfish. Continue reading