Jellyfish (English name: Jellyfish) is an important plankton in the aquatic environment, belonging to the class Mycelia. Jellyfish is a very beautiful aquatic animal. Its shape is like a transparent umbrella, and the diameter of the umbrella is large or small. 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, which is composed of endoderm. There is a thick interlayer between the two layers, which is not only transparent, but also floating. When they are moving, they use the reflection of water in their bodies to move forward. Seen from a distance, they float fast in the water like a round umbrella. Some jellyfish have umbrellas with colorful patterns. In the blue ocean, these swimming jellyfish of different colors look very beautiful.

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

The luminous principle of jellyfish has always been an important research topic. In 2008, Shimomura, a senior researcher at Woods Hole Marine Biological Laboratory in the United States, martin chalfie, a professor at Columbia University, and Qian Yongjian, a professor at the University of California, San Diego, won the Nobel Prize in chemistry for their research on the luminescence principle.