Triggerfishes are named because of the two fin spines on their dorsal (top) fins. When the fish becomes frightened, it dives into a coral head and the fish's long dorsal spine goes up. A very small second spine moves forward to lock the first spine into its upright position. The tall spine can not be pushed down until the small trigger spine is released. This makes it impossible for predators (or humans who are fish collectors) to get to the triggerfish without breaking down the coral. Triggerfishes are slow-moving carnivorous (meat-eating) fish who live in shallow water. They have eight outer teeth in each jaw and six plate-like inner teeth in their upper jaw. Some of them have beautiful markings, and they usually do not get any bigger than 2 feet in length.

Barracudas are carniverous (meat-eating) torpedo-shaped fish that vary in size from 18 inches to about 6 feet long. They can be recognizes by their lower jaw, which juts out past the upper part of their mouth, and their fanglike teeth. Some divers fear them more than sharks because they are more curious about people than sharks and have been known to follow people. Unlike a shark, a barracuda makes a single attack and leaves a wound with no jagged edges. The great barracuda is a species that is very dangerous in the West Indies but has not been known to attack people in the Hawaiian region. Various species of barracuda live in different parts of the world, including the Atlantic and Pacific Oceans and the Mediterranean Sea.