Emperor Angelfish: Species Profile

The brightly colored Emperor Angelfish (Pomacanthus imperator) is a vivid addition to your marine aquarium. These aggressive fish are happy to graze on many invertebrates and need a lot of room, but this impressive fish will add bold contrast to your fish collection. Watching the amazing color transition from juvenile to adult makes this a unique marine fish and a memorable experience for many fish keepers.

Characteristics

Origin and Distribution

Emperor Angelfish are found throughout the Indo-Pacific regions, including the Red Sea, Eastern Africa, Japan, the Great Barrier Reef and New Caledonia. Sightings have also been reported in Hawaii, Puerto Rico and Florida, most likely from inappropriate captive release. Remember, if you purchase one, you are responsible for the entire lifespan of this fish! The Emperor Angelfish will need more room than many other marine tropicals, so be sure to plan ahead.

In the wild, Emperor Angelfish congregate along coral reefs in shallow waters. Juveniles prefer hiding under ledges and as subadults, move to reef holes along surge channels, where meals are plentiful. Adults live in caves and ledges in calmer reef waters, often in male-female pairs or harems of one male with multiple females.

Due to their severe color differentiation, juveniles were thought to be a completely different species until the 1930s.

Colors and Markings

The Emperor Angelfish juvenile has a bold contrast of royal blue, black and white stripes extending across its body in an arch pattern with spots on their dorsal, caudal and anal fins. They are very similar in appearance to juvenile Koran Angelfish (Pomacanthus semicirculatus), also known as the Semicircle Angelfish. You can distinguish between the two by the complete white circle at the tail base of the Emperor Angelfish whereas the Koran has a "c"-shape.

Adults are brightly colored with yellow and dark blue stripes horizontally across the body. The mouth will be white or light grey with the forehead and operculum a dark blue to black. Although it may not look like it, this pattern is excellent for blending in with a colorful reef background. The stripe pattern helps break up a fish hiding in a reef with contrasting light and shadows.

Tankmates

As a semi-aggressive fish, the Emperor Angelfish may not play well with more peaceful fish. They will naturally prey on invertebrate species, including soft corals, sea stars, clams and anemones.

It is best to keep only once adult Emperor Angelfish per tank. If you have multiple fish per tank, it is best to keep fish in bonded male-female pairs.

The best tankmates for the Emperor Angelfish are smaller, aggressive fish, such as dottybacks, wrasses and damselfish. Large semi-aggressive fish, such as tangs and other large angels should be closely monitored, but may get along okay if properly introduced all at once to limit competition for territory and in a big enough tank. Remember, the Emperor Angelfish needs a minimum of 175 gallons to start.

Emperor Angelfish Habitat and Care

This type of fish is not for the beginner fish keeper. Advanced intermediates who have mastered saltwater tank setup and care are the only ones who should consider these lively fish.

In the wild, one Emperor Angelfish may have a very large territory, so this will translate to a large tank size. 175 gallons is bare minimum for one individual, but bigger is always better, no matter what type of fish you keep. Like many other marine tropicals, keeping their water quality pristine is key to good health and longevity.

Since they like to graze, having ready access to live rock is crucial. You should plan on having a little extra as they nibble it down. Emperor Angelfish also like to find a cave of their own, so make sure there are plenty of spots for all fish varieties in the tank who like a cozy cave.

Keep in mind that your invertebrates, including clams, corals and sea stars, might be nipped by Emperor Angelfish, so either give them places to hide or keep them out of the tank.

Emperor Angelfish Diet and Feeding

Wild Angelfish graze on a variety of foods, including algae, invertebrates and corals. Like many other tropical saltwater fish, they eat throughout the day, a trait that should be mirrored in their captive counterparts as best as possible.

In captivity, Angelfish can be fed a staple marine omnivore pelleted diet. You should supplement their diet with dried seaweed, algae-based dried food, frozen crustaceans, and a variety of other frozen diets. It is best to give them a varied diet of about 50 percent pellets (can be multiple varieties mixed together) in addition to a minimum of two other frozen or dried options. This will provide the best well-rounded diet.

Since they are grazing tropical fish, you will need to feed them 2-3 times per day. Due to their aggressive nature, spread the food out throughout the aquarium so all occupants get a fair share.

Sexual Differences

Although very subtle, adult male and female Emperor Angelfish differ in color. Males will have darker coloration just behind their eyes and female colors overall tend to be less vibrant. Without having a sexually mature male and female next to each other, it is very hard to differentiate the sexes. Males also tend to be slightly larger than adult females.

Breeding the Emperor Angelfish

Emperor Angelfish have not been bred successfully in captivity at this time.

In the wild, male and females will surface to spawn. External fertilization will occur and the eggs will be swept over the reef. This strategy allows a small percentage of the thousands of eggs produced to find safe places away from predators.

More Pet Fish Species and Further Research

If you’re interested in similar species, check out:

• Lemonpeel Angelfish
• Regal Angelfish
• Flame Angelfish