In Competitive Strategies on the Coral Reef, narrator Sir David Attenborough describes how grouper and lionfish handle being predators in the same space in the coral reef. Learn how a pair of harlequin shrimp attempt to take a starfish for a meal. This video is excerpted from BBC’s Blue Planet, a definitive documentary series diving into the mysterious depths of the sea to discover the natural history of the world’s oceans and the rarely seen marine life that reside there.