The Atlantic horse mackerel is a gregarious fish with a long, slim body free of finlets. It has a grey to silver underside, while the dorsal area is often bluish-green. As an adult it can reach a length of 50 cm and its weight generally ranges from 150 to 200 g. It is one of the most voracious fish and is always quick to bite baited hooks. It usually lives in very deep water in the Mediterranean, its ideal natural habitat, although it often approaches the coast in search of food. Vast shoals of Atlantic horse mackerel form in offshore waters, where they feed on crustaceans, cephalopods and other fish. The young gather in groups under jellyfish (especially Rhizostoma pulmo and Cotylorhiza tuberculata), where they find shelter, being immune to the poison in the jellyfish’s nematocysts. The young of other species, such as the greater amberjack, behave in the same way. Net fishing catches young specimens of the Atlantic horse mackerel, which generally keep close to the coast. The minimum size is 15 cm.