The black marlin is considered the fastest fish in the ocean, reaching up to 132 km/h. Sailfish, Swordfish, Yellowfin Tuna, Wahoo and Bluefin Tuna are also some of the fastest fish, reaching 110 km/h, 97 km/h, 80 km/h, 77 km/h and 70 km/h respectively. These species are capable of such speeds due to their torpedo-shaped bodies and specialised muscle systems.