Fish Focus: Emperor Angelfish

The Emperor Angelfish is also known as Imperial Angelfish and Imperator Angelfish. Its habitat ranges from East Africa and the Red Sea, to Hawaii and southward all the way to Australia's Great Barrier Reef.

This type of angelfish is a reef-associated species. Juveniles choose to stay hidden under ledges or inside of outer lagoons and reef flats. Larger adult specimens are found in areas of heavy algae growth, seeking shelter in caves and also under ledges. 

Juvenile Emperors are colored very differently from the adults. The juvenile Angelfish has a deep, dark blue body with concentric white circles.The dorsal fin edge is also white. Juveniles begin to change coloring when they are anywhere from 3 to 6 inches. This color change can take place in as little as 4 months or as long as a year, depending on the fish's diet and stress levels.

The adult fish is blue and decorated with close-set horizontal yellow stripes on the sides and dorsal fins. The caudal fin is a striking yellow to orange color. The pectoral fin base is black and the snout is white.

The Emperor Angelfish is moderately difficult to keep and not really recommended for the novice aquarist. It should only be placed in mature, stable aquariums with ideal water conditions. It should not be kept in a tank smaller than 100 gallons, probably needing up to a 200-gallon tank if you want this fish to thrive. The aquarium should include plenty of live rock for grazing, and also contain a number of suitable hiding spots for the fish.

The Emperor Angel is a semi-aggressive type of fish. It is highly territorial toward members of its own species as well as angelfish from other species. Angels of different sizes can possibly be kept together if the smaller specimens are introduced into the tank first.

The Emperor Angelfish enjoys a wide variety of foods but usually adapts well to a diet consisting of various meaty foods, such as shrimp. It can normally adjust to eating fresh, frozen, formula, and dry food, in addition to live food. Serving a high-quality angelfish preparation is also recommended. A diet that is not vitamin-rich enough will diminish the colors of adult angelfish.