There are many varieties of the 4-Eye Butterfly Fish.
Why do they appear to have 4 eyes?
One of the reasons for the spots on tail is an aid for the fish to camouflage themselves on the coral reefs.
Most butterfly fish have pointed snouts, useful for plucking out the small coral animals and getting into small crevices for tiny invertebrates which they feed on.
To a predator, the large dark spot on the tail appears to be the fish’s head and often allows the butterfly to escape being the “blue plate special” of the day.