We carry wholesale Banded Tun shells, Tonna sulcosa, also called tonna sulcosa, large shells for hermit crabs measuring approximately 4 inch to 4-1/2 inch in size. Banded tun shells or tonna sulcosa shells are from the family Tonnidae. These shells are light weight and are great shells for hermit crabs. Banded tun shells are also used in making seashell ornaments, shell characters, candles and in shellcraft and shell art. Tun shells are thinner and usually roomier than helmet shells. They are almost exclusively tropical, prefer deeper water, and feed mainly on fish, seaurchins and crustaceans. Their free-swimming larval life is lengthy and has helped some species to spread great distances.