barracuda, slender, elongated fish of tropical seas. Barracudas have long snouts and projecting lower jaws armed with large, sharp-edged teeth. They are ferocious, striking at anything that gleams, and are considered excellent game fishes. The largest of the group, the great barracuda, averages 5 ft (1.5 m) in length but may reach 10 ft (3 m); it is dangerous to swimmers wearing shiny objects. Other species are the Pacific barracuda (4 ft/1.2 m long) and the smaller Northern barracuda, which is not dangerous. Barracudas are classified in the phylum Chordata, subphylum Vertebrata, class Osteichthyes, order Sphyraenoidei, family Sphyraenidae.

Any of about 20 species of predaceous marine fishes (family Sphyraenidae) found in all warm and tropical regions and in some more temperate areas. Swift and powerful, barracudas are slender and have small scales, a jutting lower jaw, and a large mouth with many large, sharp teeth. They vary in size from relatively small to 4–6 ft (1.2–1.8 m) long. They are primarily fish eaters. They are popular sport fishes and are caught for food, though in certain seas they may become contaminated with a toxic substance. Bold and inquisitive, they are potentially dangerous to humans when large.

Learn more about barracuda with a free trial on Britannica.com.