Crustaceans includes crabs, lobsters, crayfish, shrimp, krill, woodlice and barnacles.
Since they spend their lives immersed in mineral rich water, crustaceans are excellent repositories of those same minerals, including zinc, iodine, selenium, and magnesium, along with vitamin A and B-vitamins (especially B12). Humans can get these nutrients on land through other animals and some plants, but rarely can they get them in such a concentrated, easy-to-consume form.
Most crustacean used in sushi are considered to taste sweeter after they are lightly poached.
With the exception of sweet shrimp, all crustacean are poached and shocked in ice water before they are used for sushi. Sweet shrimp is also a name given to a group of shrimp in the same genus that apply to the shrimp commonly used raw in sushi restaurants.
Mantis Shrimp Shako
Sweet Shrimp Amaebi