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Emperor Angelfish: The ruler of the reef

The emperor angelfish (Pomacanthus imperator) is a species of pomacanthid perciform actinopterygian that lives in coral reefs in the Indo-Pacific. It stands out for its attractive colors and its remarkable transformation from juvenile to adult state. It is also a popular aquarium fish.


It is a typical angelfish, with a thick, laterally compressed body, and a small mouth with minute teeth. It only has one dorsal fin, unlike many perciforms. It has 13-14 dorsal spines, 17-21 dorsal soft rays, 3 anal spines and 18-21 anal soft rays.

Adult emperor angelfish are colorfully colored: a black mask that extends from the eyes to the beginning of the trunk, a yellow body with horizontal blue stripes, a yellow tail, and a violet anal fin.

Juveniles are dark blue with a white margin of the caudal fin and dorsal fin, and white semicircular lines, alternating with other light blue ones, in the center of which there is an ovoid line, located in front of the caudal fin. This coloration is very similar to that of the juveniles of the species Pomacanthus semicirculatus, and the most noticeable difference is that the white “C”-shaped line, located on the back of the body, in the case of P. imperator is more closed, and inside it has an ovoid-shaped line, and others in the form of circles located on the anal and dorsal fins. While the juvenile P. semicirculatus, both inside the “C” and on the fins, have small elongated irregular lines.

It measures up to 40 centimeters, weighs up to 1.4 kilos. A longevity of 14 years has been reported. If it’s scared, it makes a strange noise. Amoxicillin for fish  ampicillin for fish

Juvenile livery fish

Habitat and distribution

It is a benthopelagic, reef-associated and non-migratory species. It occurs between 1 and 100 m deep. Its temperature range is between 23.44 and 29.17 °C. Found in a wide variety of habitats, from outer reefs, to deep lagoons, and often in areas of rich coral growth. They are frequently seen near ledges and caves. Juveniles are often under ledges or in shallow reef holes.

It is a common species, with stable populations. It is distributed in the Indo-Pacific, being a native species of Saudi Arabia; Australia; Bahrain; Bangladesh; Burma; Cambodia; China; Cocos (Keeling) Islands; Comoros; cook islands; Egypt; United Arab Emirates; Eritrean; Philippines; fiji; Guam; Hawaii; Hong Kong; India (Andaman Is., Nicobar Is.); Indonesia; Iran; Iraq; Israel; Japan; Jordan; Kenya; Kiribati; Kuwait; Madagascar; Malaysia; Maldives; Northern Mariana Islands; Marshall Islands; Mauritius; mayotte; Micronesia; Mozambique; Nauru; Christmas Island; Niue; New Caledonia; Oman; Pakistan; Palau; Papua New Guinea; Pitcairn; Polynesia; Taste; Meeting; Solomon Islands; samoa; Seychelles; Singapore; Somalia; Sri Lanka; Sudan; Taiwan; Tanzania; Thailand; Tokelau; Tonga; Tuvalu; Vanuatu; Vietnam; Wallis and Futuna; Yemen and Djibouti.


Emperor angelfish feed on sponges, tunicates, hydroids, and other encrusting organisms, as well as algae. It has a digestive system capable of digesting those tissues.


This species is oviparous. Males have harems of 2 to 5 females. They are sequential hermaphrodites, which means that if a male dies, one of the females in the harem becomes a male. Fertilization is external, spawning once a year depending on the weather season. They do not care for their fry.


Emperor angelfish are a difficult species to keep in captivity. It requires excellent water quality, free of phosphates or nitrates, weekly water changes of 5% of the volume are recommended. It requires an aquarium of at least 378 liters for a single specimen, doubling that amount if a couple is housed. The aquarium should have rocks and caves for it to hide.

The diet must have vegetable substances and sponges, it also accepts artemia and mysis, or food in flakes or pellets. You can prepare a mixture of mussels, shrimp, squid and spinach. It is recommended to feed in small amounts and three times a day.

It is not suitable for reef aquariums as it will peck at corals.