Skipjack can be distinguished from other tunas by the presence of stripes on the belly. Usually 4-6 prominent, dark longitudinal stripes from the lower belly and sides toward the tail. The top of the fish is a dark purplish-blue, and the lower flanks and belly are silvery. The pectoral and ventral fins are short, and the two dorsal fins are separated at the base by a small interspace. The teeth are small and conical. No swimbladder is present. There are 53-63 gill rakers on the first gill arch, more than any other tuna. Common size: 16 to 28 inches.