Description
Porcupinefish (Diodontidae) are a large family of bony fish in the order Tetraodontiformes (suborder: Tetraodontoidae). A special genus in this family is Diodon. Porcupinefish are sometimes confused with pufferfish (or Tetraodontidae). However, unlike pufferfish, pufferfish do not bear spines on their skin. Furthermore, pufferfish can move their spines (a kind of movable rays) and have a strong mouth with which they can crush their prey. Fish from other genera of the Diodontidae family (such as Chilomycterus), on the other hand, have fixed, immovable spines. Like pufferfish, porcupinefish can inflate their bodies by swallowing water or air, causing them to swell into a ball. Their greatly increased volume then protects them from attacks by predatory fish. The sharp, outward-folding spines provide a second defense mechanism. Some species are venomous due to the substance tetrodotoxin in their skin or intestines. Because of these characteristics, porcupinefish have little to fear from predatory fish, except perhaps from sharks or killer whales, although young specimens are also hunted by tuna and dolphins.
