Emperor Angelfish

The emperor angelfish, Pomacanthus imperator, is a species of marine angelfish. It is a reef-associated fish, native to the Indian and Pacific Oceans, from the Red Sea to Hawaii and the Austral Islands.
Juveniles are dark blue with electric blue and white rings; adults have yellow and blue stripes, with black around the eyes. It takes about four years for an emperor angelfish to acquire its adult colouring. They grow to 40 cm (15.75 in) in length. Juvenile to adult transition may not fully occur in an aquarium.