Juvenile giant pufferfish (Arothron stellatus). When threatened, pufferfish gulp down water. This causes them to swell to up to twice their normal body size. It is a solitary animal found in the tropical Indo-West Pacific. It feeds on corals, sponges and crustaceans, crushing and grinding them with its powerful jaws and sharp teeth. Pufferfish are a delicacy in Japan, where they are eaten as sushi. However, they contain a powerful toxin, tetrodotoxin, that is fatal to humans, and so need to be prepared with care. Photographed in Lembeh Strait, North Sulawesi, Indonesia.