SAILFISH, any of a group of large marine sport fishes with very long rays and dark spots on the large sail-shaped dorsal fin.
Sailfish also have spearlike snouts, or bills, and ridges on the sides of the caudal peduncles just in front of their tails. They are found in warm coastal waters throughout most of the world. The Pacific sailfish (Istiophorus orientalis) is the largest species, reaching a length of more than 11 feet (3.3 meters) and a weight of more than 200 pounds (90 kg).
The Atlantic sailfish (I. albicans), one of the most popular game fishes along the East Coast of the United States, is somewhat smaller. Folding their “sails” against their bodies, sailfish swim very rapidly, sometimes striking at smaller prey fishes with their bills. Sailfish, together with spearfish and marlin, are classified in the family Istiophoridae of the order Perciformes.