Moon jellyfish (Aurelia) is the most widespread of the jellyfish species. There are four heart-shaped stomachs and four oral arms like ribbons in the middle of translucent white umbrella. When it floats on the sea, it looks like a bright moon in the sea, so it get its name. They move at a frequency similar to human brain waves, and their rhythmic “swimming” will relax people’s mood and help relieve pressure. Here, thousands of them swim in the tank with the switching lights, which is very vivid.