Pronunciation: (pôr'kyu-pīn"fish"),[key] —n., —pl.(esp. collectively)-fish,(esp. referring to two or more kinds or species)-fish•es. any of several fishes of the family Diodontidae, esp. Diodon hystrix, of tropical seas, capable of inflating the body with water or air until it resembles a globe, with erection of the long spines covering the skin.