These are goatfish in their normal color. When they want to be cleaned
they go to a cleaning station and turn red as a signal that they want
to be treated (Bonaire).
A juvenile Emperor Fish. This youngster is not recognized
by its parents as belonging to the same species because of its totally
different color, and is therefore allowed to live in the same territory
by the adults which would chase away any other Emperor Fish from their
territory because they cannot allow competition for food. The young
ones are not competitors as they have a different diet from the adults.
By the time the fish is large enough to conquer a territory of its own,
it changes color to the adult phase, as well as its diet (Indo-Pacific).