Species name: Pomacanthus Imperator
Common names: Emperor or Imperial Angelfishe
Family: Pomacanthidae (Angelfishes)
Order: Perciformes (perch-likes)
Class: Actinopterygii (ray-finned fishes)
Maximum Length: 15.7 in.
Minimum tank size: 140 gal.
Aggressiveness: Generally peaceful in the aquarium but can be aggressive towards other Emperor Angelfish and other large angelfish species.
Reef Compatibility: Will nip at some LPS, soft coral like Xenia and clam mantles. Will do well with SPS and noxious soft coral.
Diet: It is a sponge eater and a steady diet of sponges is something challenging to reproduce in an aquariums. A varied diet should be provided 3 times a day and should include Spirulina, mysid shrimp, frozen shrimp, vitamin enriched food, color enhancing food and marine algae.
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Emperor angelfish live near ledges and caves in areas of rich coral growth of the Indo-Pacific and the Red Sea at depths of 3 to 233 feet. The aquarium should reproduce its natural habitat and include plenty of live rock for grazing and suitable hiding spots such caves.
It is not an hardy fish and it is one of the more expensive marine fish available in the hobby so they should only be introduced in a well established tank with ideal water conditions. Best water conditions for this fish are as follows: Temperature between 72 and 78° F with a pH of 8.2 to 8.4, sg 1.020-1.025 and dKH at 8 to 12.
Young specimens are dark blue with electric blue and white rings. As they grow older, they will have yellow and blue stripes, with black around the eyes. It takes about four years before it acquire its adult coloring. Older individuals are prone to color loss and mental and lateral erosion. This is most likely due to a nutritional issue.
Since adults are territorial, the change in color is thought to allow juveniles to enter adult territories without being chased out.
They are prone to parasites and should be kept in a quarantine tank for a few weeks before introducing them into an aquarium.