The bullet tuna, Auxis rochei rochei, is a subspecies of tuna, in the family Scombridae, found circumglobally in tropical oceans in open surface waters to depths of 50 m (164 ft). Its maximum length is 50.0 cm.(20 inches) Sometimes called bullet mackerel, the bullet tuna is a comparatively small and slender tuna. It has a triangular first dorsal fin, widely separated from the second dorsal fin, which, like the anal and pectoral fins, is relatively small. There are the usual finlets of the tuna. There is a small corselet of small scales around the pectoral region of the body.