Jeremy Wade returns to Australia's predator-packed Fitzroy River in search of one of the world's rarest and least known fish - the Northern River Shark. It's so elusive that only twenty have ever been caught.

A look at the ways marine animals attack and the physical attributes that make them so dangerous.

Jeremy recalls close encounters with dangerous marine animals, including wolf-fish and whaler sharks.

Jeremy discusses a few species of catfish he has come across that strike him as the most deadly and dangerous of the catfish family

Jeremy Wade re-lives some of his most frightening encounters with the world's most deadly catfish.