Sailfish

Sailfish are a genus Istiophorus of billfish living in warmer sections of all the oceans of the world. They are predominantly blue to gray in colour 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. They are therefore described as billfish in sport-fishing circles.