Foureye Butterflyfish

A local fisherman caught this using a cast net in shallow water along the shore of the island. This, along with some other by-catches, he gave to the boys to examine. Arthur identified it as a Foureye Butterflyfish. It was a beautiful yellow colour, with distinctive markings- a vertical stripe across the eye and the spot near the tail, as well as the diagonal body stripes. This specimen was about 1.5 inches in length.

Foureye Butterfly fish have bristle-like teeth, and feed mainly on invertebrates such as polychaete worms, as well as gorgonians and tunicates. The large spot near the tail could be a way to confuse predadtors, who may mistake the tail for the head of the creature- it may be easier for the butterflyfish to evade any predators that aim to strike the head-end of the fish first. There are other potential purposes to the eye-spot, including a warning to predators, communication with other fish or intimidating prey. When a Foureye Butterflyfish cannot escape a predator, it sometimes faces it head-on and raises its spikey dorsal spines, appearing ready to charge!

https://en.wikipedia.org/wiki/Foureye_butterflyfish