BUTTERFLY FISH COLORING

The coloring of adults is often slightly different from that
of juveniles (size less than 5 cm), the black patch on the
rear of the dorsal fin sometimes disappearing in adults.
It seems to act as a false eye (the real one being surrounded
- and hidden - by a band or black patch) to
deceive an enemy and surprise it by fleeing "in reverse."
However, this theory has yet to be proven. Once the fish
are fully grown, the juvenile bands can fade or disappear
completely, although some, in contrast, can get bigger.