I was recently teaching a PADI Advanced Open water course, doing the deep dive at Chumphon pinnacle, the weather was great, flat seas, sun shining, and crystal clear water, throughout the dive there were big groups of yellow tail and great barracuda all over the site.
The barracuda is a ray-finned fish known for its large size and fearsome appearance. Its body is long, fairly compressed, and covered with small, smooth scales. Some species could reach up to 1.8m in length and 30 cm in width. The barracuda is a salt water fish, and is found in tropical and subtropical oceans worldwide.
The collective name for a group of barracudas is a battery. They are voracious, opportunistic predators relying on surprise and short bursts of speed (up to 27 miles per hour) to overtake their prey.
Adults of most species are more or less solitary, while young and half-grown fish frequently congregate. Barracuda prey primarily on fish (which may include some as large as themselves).
To finish off the course we did the night dive at White rock, where we followed some great barracuda while they were hunting, using our torch light to hunt small fish.