Red Sea fishes: Emperor Angelfish (Pomacanthus imperator) – Video

Video credit: Patricia Martin Cabrera (United Arab Emirates)

Review: Abdel Rahman El Gamal (Founder of the video channel)


Introduction: The Emperor Angelfish (Pomacanthus imperator), is a reef-associated marine angelfish and is also called the Imperator Angelfish or Imperial Angelfish. The species is one of the most stunning underwater fish. Their color and graceful shape make them one of the top contenders for any beauty contest. It is possibly the most easily recognized fish in the Red Sea. The species makes a fantastic display whether in the wild or in aquariums.

Description: Emperor Angelfish have deep and slightly elongated with small white mouths. Their flattened shape enables them to wind their way amongst the corals as well as to retain their stability when manoeuvring to pick their food. Adults of emperor angelfish vary in size from as small as 10 cm to up to 40 cm in the wild.

The body of an adult emperor angelfish is vibrantly colored, with yellow and royal blue horizontal lines streaming across their frame. It also has a dark mask-like stripe across its eye area which helps the fish to confuse predators. During mating, the color of male’s mask turns dark blue, almost black, while the female’s mask will turn a bland color.

The pretty angelfish juveniles look totally different from adults. They are dark blue with white and electric blue curved strips (rings) and a honeycomb pattern on the top and bottom fin and tail made up of black spots edged in blue. As a juvenile emperor angelfish grows, its color gradually changes towards that of the adult ending by replacing all juvenile color by the adult color characteristics. It takes about 24 to 30 months for an emperor angelfish to acquire its adult coloring.

It is believed that a juvenile 10 -14 cm in length is the best sized emperor angelfish for adjusting to life in a captive environment such as aquaria. Also, the color changes in captivity may occur earlier than it would in the wild, and the final adult coloration may not be as splendid as that seen in a wild-caught adult emperor angelfish.

Geographic range: The emperor angelfish, Pomacanthus imperator, is native to the Indian and Pacific Oceans, from the Red Sea to Hawaii and the Austral Islands. The species inhabits in a wide geographical range of the world’s oceans from the Red Sea all the way east to Australia’s Great Barrier Reef and the Hawaiian Islands. In recent years, the species have migrated through the Suez Canal and started to colonize areas in the Mediterranean coast. As a result of aquarium release, some populations of the species have been observed outside their natural range such as Japan, Australia and others.

Habitats: Emperor angelfish adults live in or close to reefs at depths ranging from 1-100 m. They can be found hiding in caves in areas of rich coral growth on clear lagoon, seaward, or channel reefs. Adults are more often seen patrolling over the open reef. Juveniles and sub-adults inhabit the mouth of caves and surge channels and often found under ledges or in holes of shallow reef flats.

Feeding habits: Adults of emperor angelfish adults are omnivorous feeding on small invertebrates and plants with a preference to sponges and algae. Their bulky and strong jaws enable them to crush hard-shelled crustaceans and to chew the sponges. The digestive tract of the emperor angelfish coats ingested food with a layer of mucus in order to further protect itself from the sponge’s sharp tiny needle-like silica. However, emperor angelfish juveniles feed on parasites as well as dead skin of larger fish and have been sometimes seen cleaning other fish such as moray eels.

Reproduction: Emperor angelfish adults are so territorial, and they will typically defend their living space with often two females. They may even attack other male emperor angelfish who try to enter their territory. The fish are protogynous which means they are born as females and develop later into males.

Upon mating, the pair will leave the reef to the surface whereas eggs are released by females and fertilized by males where fertilized eggs can be taken away on currents back and dispersed in the reef zones where they hatch and continue their life cycle.



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