Jellyfish is a representative of the animal world of the seas and oceans. This creature from the class of hydroids lives mainly in salt water at a temperature of 26-33 ºC. The asexual form (polyps) can exist at lower temperatures (12-20 ºC). Their habitat is located in the Pacific, Atlantic and Indian oceans, as well as inland seas of the equator, the tropics, subtropics and temperate climate. The biological purpose of jellyfish is the purification of water from organic debris. Therefore, they constantly migrate. They often bring to the polluted waters of the coastal strip.
There are jellyfish record-breakers. The Cyanea arctic jellyfish, which lives in the northwest Atlantic, reaches 2.5 m (body) and 36 m (tentacle diameter). This species differs not only in size, but also in cold resistance. Arctic Cyanea was found even in the waters of the Arctic Ocean. Next to the polar bears. But at the same time, they were never found in the water area of the Southern Hemisphere. One of the deep-sea species of jellyfish is Colobonema sericeum, descends to 1500 m.
Along the coast of Northern Australia and the adjacent seas there is a particularly dangerous form of jellyfish – Chironex fleckeri or Wasp. Their sting causes the death of an adult person in 3 minutes.