Almost all Mafia's best diving is at depths of less than 30m so it is a sport diver's paradise. The reefs of the archipelago offer a staggeringly beautiful and varied display of marine life. The excellent condition and high diversity of the reefs stimulated the creation of Mafia Island Marine Park, Tanzania's first marine park. Examples of most kinds of tropical marine habitat occur here, including exposed fringing reefs, rock walls, and soft coral and algae-dominated reefs. The diversity of animal and plant life is hard to match, with over 48 genera of coral and 400 species of fish so far identified.