河豚、箱鱼、刺鱼和刺豚属于三个密切相关且相似的科：河豚科（Tetraodontidae）、刺鱼科（D

ontidae (pufferfish, also known as globefish, and canthigasters) are known for their ability to inflate themselves impressively when in danger. Their teeth are fused together to form a powerful beak divided into four parts, hence their name tetra-odon, which means four teeth. They have no scales, their skin is covered with mucus, and they often possess powerful toxins such as tetrodotoxin in their internal tissues. Diodontidae (porcupinefish), also known as sea urchin fish, are recognisable by their spines or quills, which stand up when they inflate themselves to impress or deter predators. They are also toxic. Their powerful mouths allow them to consume marine invertebrates, sea urchins and sometimes even corals. Ostraciidae (boxfish) have a body enclosed in a kind of exoskeleton. This acts as a kind of armour and is their main defence, as they cannot inflate themselves like the other two families. When under intense stress, they can secrete a powerful toxin, ostracitoxin, which is capable of killing other fish. All three families live near tropical coral reefs, feed on zooplankton, algae and shellfish, and grow to between 2 cm and over 1 m in length, depending on the species.