Jellyfish (English name: Jelly? Fish): It is an important plankton in the aquatic environment, belonging to the class Echinotheca. Jellyfish is a very beautiful aquatic animal. Its body shape is like a transparent umbrella, the diameter of the umbrella is large or small, and the diameter of the umbrella of the big jellyfish can reach 2 meters. There are some whisker-like tentacles on the edge of the umbrella, and some tentacles can be as long as 20-30 meters.

The main component of jellyfish body is water, and it is composed of inner and outer germ layers. There is a thick mesothelium between the two layers, which is not only transparent, but also floating. When they are moving, they use the water spray reflection in their bodies to move forward. From a distance, they look like a round umbrella floating rapidly in the water. Some jellyfish have umbrellas with colorful patterns. In the blue ocean, these swimming jellyfish with different colors look very beautiful.

They are found in tropical waters, temperate waters, shallow waters, oceans about 100 meters deep, and even fresh water areas. Jellyfish existed as early as 650 million years ago, even before dinosaurs. There are more than 250 species of jellyfish in the waters of the world, which are distributed in waters all over the world. All live in the ocean.