The red hair of frozen shrimp shows that it is not fresh, because there is an unstable pigment-astaxanthin in the case of shrimp and crab. After the death of shrimp and crab, astaxanthin will go through a slow oxidation process and turn red, so it should be avoided.

Shrimp, an arthropod living in water, belongs to arthropod crustaceans, and there are many kinds, including Antarctic red shrimp, green shrimp, river shrimp, grass shrimp, prawn, prawn and lobster. Shrimp has high nutritional value for dietotherapy, can be steamed and fried, and can be used as Chinese herbal medicine.