Valued food and game fish in the genus Istiophorus (family Istiophoridae) of warm and temperate waters worldwide. It has a long, rounded spear extending from its snout but is distinguished from marlins and related species by its slimmer form, long pelvic fins, and especially its large, sail-like dorsal fin, which is bright blue and spotted. Deep blue above and silvery below, they grow to about 11 ft (3.4 m) long and 200 lbs (90 kg) or more. They feed mainly on other fishes. Its classification is uncertain, and one (I. platypterus) to several species may be recognized.