Tuna is a very fighter and strong fish. The caudal peduncle is very sharp. The lateral line is not horizontal but curved away from the dorsal fin. The mouth reaches the eye. It has small teeth on the palate and the vomer bone. Belly color
Silver and light blue sides. Very intense blue loin almost black in its zenith line. First blue or black dorsal fin (dark). Second YELLOW dorsal fin in recent livery. This yellowfin is a differentiator of bluefin tuna.
From the back there are vertical lines that in young specimens clearly show clear spots (white spots). The belly is white. At the end of the body it has yellowish, with a very narrow dark border. The eyes are small, made especially noticeable in adults. The body is plump and sharp near the tail. Its pectoral fins are small in proportion to the body, which is wider than the bonito (more domed). The head is less elongated than the head of the bonito. Below one meter of size (mouth-tail) IS NOT SEXUALLY MATURE. You can swim up to 90Km / h (40 Knt).