Grant Brokensha

We know Bull Sharks swim upriver and we know they hunt in the sea. But we've never been able to see it all like this. We see them attack and consume other sharks. We watch their shady hunts in the deep. We follow them up freshwater rivers to pupping grounds. We see them hunt shoals of fish from drones above and we watch as they clash with hippos and crocodiles.

The plains of Africa have always been a hotbed of predator action, but lurking in its rivers is perhaps its most elusive killer: the Goliath tigerfish. Legends say they are man-eaters, that even crocodiles fear them. Locals call them "demon fish" but angling legend Andy Coetzee calls them something else: an obsession. He dives into the predator-infested Okavango Delta and the treacherous Congo River on a mission to finally land what is considered to be the hardest fish in the world to catch.