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The Emperor angelfish looks completely different in its adult- and juvenile life stage. The male and female adults look similar, but can be distinguished by the color of the face. Male have a bluish and females have a grayish face (in front of the eye mask). It can reach up to 40 cm. Adults are found under ledges and caves where there is plentiful coral, in seaward reefs, channels or clear lagoons. They are found at depths from 1 to 80 meters. Their main food contains sponges and tunicates.