The arthropods are prawn, horseshoe crab (Tachypleus tridentatus) and Portunus (Portunus trituberculatus). It is an ancient arthropod living in the ocean. It first appeared 400 million years ago, earlier than the appearance of dinosaurs. The appearance of the Chinese river sturgeon you see now is basically the same as its appearance 400 million years ago. Horseshoe crab has a special physiological feature, its blood is blue, that is because the blood contains 0.28% copper ions. In addition, scientists have extracted the “sturgeon reagent” from the blue blood, which is very useful. When a person is sick, it can be used to quickly and accurately detect whether it is caused by bacterial infection. It can also be used to monitor toxin contamination in the pharmaceutical and food industries.