Researchers have captured a POV video of the world's fastest fish hunting for the first time.

Sailfish live on the open ocean and do not survive in captivity, making them extremely hard to study.

The sailfish is widely considered the fastest fish in the ocean and can swim nearly 70 miles per hour.

Researchers from the Nova Southeastern University in Davie, Florida, USA, managed to catch one of the elusive fish and fit it with a camera.

The video, recorded off the coast of Panama, shows the 45kg fish catching a small tuna in a frenzy.

Thanks to the footage, researchers were able to ascertain how much food Sailfish need to eat every day.

The insights into the species' diet was an accidental bonus as the researchers had initially tagged the fish to find out how long it takes a sailfish to recover after being caught and released by a fisherman.

Ph.D. student Ryan Logan, who led the research team, hopes that this information will prove beneficial in the protection of the species.