The narrow-lined puffer fish has no scales and feeds on molluscs and other invertebrates in the sea bed. Like other puffers, it expands when threatened, presenting a challenge to any would-be predator. Puffers contain powerful toxins in their internal organs and skin, and are thought to be the second-most poisonous vertebrates on earth after the golden poison frog. Puffers are eaten in Japan, prepared by specially-trained chefs who know how to remove the toxic organs.