Crustaceans are fragile marine animals whose flesh, shielded by an external skeleton, should be protected to optimize its consumption. The largest and most expensive of them (crabs, lobsters, etc.) can be marketed alive for optimal freshness. They are then extracted from a fish tank at the time of the sale, and it is up to the buyer to take care of their killing during cooking. Alive, the crustaceans must be able to move and have intact legs and claws. When they are marketed dead, as here on the Trouville-sur-Mer Marché aux Poissons (Fish Market), they must be stored on ice.