The Indo-Pacific sailfish is the fastest fish in the ocean, reaching speeds of 68 miles per hour. Its body was built for speed, and the sailfish will fold its fins close to its body so that it can swim more smoothly through the water. The tuna fish is the speed champion for long distances, averaging 45 miles per hour. The fastest speed that a human swimmer can reach is about 5 miles per hour. American swimmer Michael Phelps, the most decorated Olympian of all time with 22 medals, currently holds seven world records for speed. His record time of 49.82 seconds in the 100-meter butterfly is the equivalent of 4.49 miles per hour. The 50-meter freestyle record held by Cesar Cielo of Brazil of 46.91 seconds is the equivalent of 5.3 mph.