Any species of marine bony fishes belonging to the families Tetraodontidae (puffers, blowfishes), or Diodontidae (burrfishes, porcupinefishes, spiny puffers). These fishes are able to inflate their bodies with water or air to form a globe as a protection against predation. The flesh and organs of some blowfishes contain an extremely potent toxin which can be fatal to humans when ingested.