The Foureye butterflyfish, Chaetodon capistratus, is a butterflyfish of the family Chaetodontidae found among tropical reefs around the world and concentrated in the Indo-Pacific oceanic region.
Foureye butterflyfish are deep-bodied and laterally compressed, with a single dorsal fin and a small mouth with tiny, bristle like teeth. Foureye butterflyfish mate for life and therefore they will often be seen in pairs.
Foureyes get their name due to a large, dark spot on the rear portion of each side of the body. This spot is surrounded by a brilliant white ring resembling a false eye. A black, vertical bar on the head runs down the true eye, making it more nondescript and may result in a predator confusing the back end of the fish for the front end. The four-eye’s first instinct when threatened is to flee, putting the false eye spot closer to the predator than the head. Most predators aim for the eyes, and this false eye spot tricks the predator into thinking that the four-eye will flee tail first.
When escape is not possible, the four-eye will sometimes turn to face its aggressor, head lowered and spines fully erect, like a bull about to charge. This may serve to intimidate the other animal or may remind the predator that the butterfly is much too spiny to make a tasty meal.
Foureye butterflyfish typically frequent shallow inshore waters, where they feed on a variety of crustaceans and coral polyps.
The Foureye butterflyfish is known for its uncanny ability to swim in and around coral heads and reefs. The fish is able to find its way through the most intricate passages by swimming on its side or even upside down.