Sailfish (Istiophorus platypterus)

The sailfish (Istiophorus platypterus) is the ocean's speed champion, reaching bursts of 68 mph (110 km/h) - faster than cheetahs. This sleek predator uses its namesake retractable dorsal sail and streamlined body to slash through water with unmatched agility. Found in warm Atlantic and Pacific waters, sailfish employ their blistering speed to herd and strike prey like sardines, often hunting cooperatively. Their long bills stun fish, while color-changing skin signals attacks. Though typically cruising at 7 mph, their explosive acceleration and precision turns make them the undisputed fastest swimmers, a marvel of hydrodynamic evolution.