Sailfish (Istiophorus platypterus)
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Sailfish are two species of fishes in the genus Istiophorus, living in warmer sections of all the oceans of the world. They are blue to gray in color and have a characteristic erectile dorsal fin known as a sail, which often stretches the entire length of the back. Another notable characteristic is the elongated bill, resembling that of the swordfish and other marlins.
Both species of sailfishes grow quickly, reaching 1.2-1.5 m (4-5 ft) in length in a single year, and feed on the surface or at mid-depths on smaller pelagic fishes and squid. Individuals have been clocked at speeds of up to 110 km/h (68 mph), which is the highest speed reliably reported in a fish. Generally, sailfish do not grow to more than 3 m (10 ft) in length and rarely weigh over 90 kg (200 lb), although larger specimens have been seen off the shores of Costa Rica.
The sail is normally kept folded down and to the side when swimming, but it may be raised when the sailfish feels threatened or excited, making the fish appear much larger than it actually is. This tactic has also been observed during feeding, when a group of sailfish use their sails to "herd" a school of fish or squid.
Sailfish are highly prized game fish and are known for their incredible jumps.