Cuttlefish or cuttles are marine mollusks of the order Sepiida. They belong to the class Cephalopoda, which also includes squid, octopuses, and nautiluses. Cuttlefish have a unique internal shell, the cuttlebone, which is used for the control of buoyancy. Cuttlefish eat small mollusks, crabs, shrimp, fish, octopus, worms, and other cuttlefish. Cuttlefish also have one of the largest brain-to-body size ratios of all invertebrates.
Cuttlefish are caught for food in the Mediterranean, East Asia, the English Channel, and elsewhere. In East Asia, dried, shredded cuttlefish is popular snack food. In the Qing Dynasty manual of Chinese gastronomy, the Suiyuan shidan, the roe of the cuttlefish, is considered a difficult-to-prepare, but sought-after delicacy.
Cuttlefish are quite popular in Europe. For example, in northeast Italy, they are used in risotto al nero di seppia (risotto with cuttlefish ink), also found in Croatia and Montenegro as crni rižot (black risotto). Catalan cuisine, especially that of the coastal regions, uses cuttlefish and squid ink in a variety of tapas and dishes such as arròs negre. Breaded and deep-fried cuttlefish is a popular dish in Andalusia. In Portugal, cuttlefish is present in many popular dishes. Chocos com tinta (cuttlefish in black ink), for example, is grilled cuttlefish in a sauce of its own ink. Cuttlefish is also popular in the region of Setúbal, where it is served as deep-fried strips or in a variant of feijoada, with white beans. Black pasta is often made using cuttlefish ink.
Shellfish is a colloquial and fisheries term for exoskeleton-bearing aquatic invertebrates used as food, including various species of mollusks, crustaceans, and echinoderms.
Although most kinds of shellfish are harvested from saltwater environments, some are found in freshwater. Shellfish are among the most common food allergens.