Great Barracudas are large fish. Mature specimens that are caught are usually around 60–100 cm (24–39 in) in length and weigh 2.5–9 kg (5.5–20 lb). Exceptionally large specimens can exceed 1.5 m (4.9 ft) and weigh over 23 kg (51 lb). The record-sized specimen caught on rod-and-reel weighed 46.72 kg (103.0 lb) and measured 1.7 m (5.6 ft) while an even bigger specimen measured 2 m (6.6 ft) and weighed 50 kg (110 lb). Barracudas are elongated fish with powerful jaws. The lower jaw of the large mouth juts out beyond the upper. Barracudas possess strong, fang-like teeth that are unequal in size and set in sockets in the jaws and on the roof of the mouth. The head is quite large and is pointed and pike-like in appearance. The gill-covers do not have spines and are covered with small scales. The two dorsal fins are widely separated, with the first having five spines and the second having one spine and nine soft rays. The second dorsal fin equals the anal fin in size and is situated more or less above it. The lateral line is prominent and extends straight from head to tail. The spinous dorsal fin is situated above the pelvis. The hind end of the caudal fin is forked or concave, and it is set at the end of a stout peduncle. The pectoral fins are placed low down on the sides. The barracuda has a large swim bladder.
In general, the barracuda's coloration is dark green or a blue type coloration or grey above chalky-white below. This varies somewhat. Sometimes there is a row of darker cross-bars or black spots on each side. The fins may be yellowish or dark
Barracudas appear in open seas. They are voracious predators and hunt using a classic example of lie-in-wait or ambush. They rely on surprise and short bursts of speed (up to 27 mph (43 km/h)) to overrun their prey, sacrificing maneuverability. Barracudas are more or less solitary in their habits. Young and half-grown fish frequently congregate in shoals. Their food is composed almost totally of fish of all kinds. Large barracudas, when gorged, may attempt to herd a school of prey fish in shallow water, where they guard over them until they are ready for another hunt.
Attacks on Human
There are some numberous reports about Barracudas attacking divers especially when they swim too close with this fish or bring shiny object when diving. Only 2 people known reported killed by this fish attacks.