GLOBE-FISH or SEA-HEDGEHOG, the name of some sea-fishes of the families Diodontidae and Tetrodontidae, which have the faculty of inflating their stomachs with air or water. Their jaws resemble the beak of a parrot, the bones and teeth be ing coalesced into one sharp-edged mass. By means of these they are able to break off branches of corals, and to masticate other hard substances on which they feed. Usually they are of a short, thick, cylindrical shape, with powerful fins. Their body is covered with tough skin, without scales, but provided with variously formed spines. When they inflate their capacious stomachs they assume a globular form, and the spines protrude, forming a de fensive armour. A fish thus blown out turns over and floats belly upwards, driving before the wind and waves. Many of these fishes are highly poisonous when eaten. They are most numerous in the tropics; a few species live in large rivers, as, for instance, Tetrodon fahaka, of the Nile. Nearly loo species are known.