The Emperor Angelfish is also known at the Imperator Angel. It is found in the western/central Pacific, the Indian Ocean and the Red Sea. The Emperor is not a good fish for beginners, because of their large adult size. In fact it often doesn’t live long in an aquarium managed by more experienced aquarists. It is definitely not a candidate for a reef tank.

The pomachanthid family is named after the Latin words “pom” (cover) and “acanthus” (thorn), which refers to its large spine on the lower, rear margin of its gill cover. This spine distinguishes angelfish from butterflyfish. Many pomachanthidae share a common characteristic that the young are a totally different color pattern than the adults. In fact the young of differing species can look more related to each other than to their parents. The Emperor Angelfish is typical of this pattern.

The juvenile Emperor Angelfish is blue/black with concentric white and blue stripes that appear to emanate from the tail. The pattern is easily confused with the juvenile Koran Angel, however the latter has circles that do not converge on the base of its tail. As it matures, these circles fade while the adult stripes develop in a horizontal pattern. The maturing Emperor can take on the appearance of a double exposed picture. The adult Emperor has several bright contrasting colors. It has a blue body covered with bright yellow horizontal stripes and a bright yellow tail fin. It has a distinctive black mask over its eyes and another dark vertical band behind its gills. The dark area continues on the lower body edges to the tail fin. The banding is highlighted with blue edges. The mouth area is white. The only coloring that is similar to the juvenile is along the edges of the anal fin.

The Emperor Angelfish requires a 100 gallon or larger tank with live rock for eating and hiding. Although they are always associated with coral reefs in the wild, they are not good candidates for a reef tank. They will eat away at stony corals, soft corals, feather dusters and clams. They scrape algae with their powerful jaws. In the wild their main diet is sponges. The Emperor should be fed a diet of marine algae, high-quality flake food and mysis shrimp. A varied diet is essential in helping to preserve its distinctive coloration. An excellent food choice is Angel Formula by Ocean Nutrition, which has a very high percentage of sponge in its mixture.

A better choice for a large angel is the Koran Angelfish, but if you are determined to keep an Emperor, start with young adults under 6 inches, as they seem to adapt more readily to captivity. Buy the brightest coloration and most alert specimen available. Don’t use a net to move them to the tank, as they can catch their gill spine in the mesh. Also double bag them when transporting, in case they puncture the surface of the bag. Make sure your tank is well established before introducing Emperors.

Emperors form mating pairs and are egg-scatterers. They are not successfully bred in captivity.

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