Pomacanthus imperator
Source: Kattegat Centeret - Kasper Hareskov Tygesen
Pomacanthus imperator
Source: Kattegat Centeret - Kasper Hareskov Tygesen
Pomacanthus imperator
Source: Kattegat Centeret - Kasper Hareskov Tygesen
Pomacanthus imperator
Source: JJPhoto.dk
Pomacanthus imperator
Source: Kattegat Centeret - Kasper Hareskov Tygesen
Pomacanthus imperator
Source: Kattegat Centeret - Kasper Hareskov Tygesen

Facts

Latin name Pomacanthus imperator - (Bloch, 1787)
Common name Emperor Angelfish
Family Pomacanthidae - Pomacanthus
Origin East Indian Ocean, West Indian Ocean, Australia, Japan
Max length 40.0 cm (15.7")

As aquarium fish

Minimum volume 800 l (211 gal)
Hardiness Average
Suitable for aquarium Suitable with care
Reef safe Not reef safe
Aggressiveness Might be aggressive towards other species

Food

Maybee
  • Zooplankton (Cyclops, pods...)
  • Soft coral
  • Large polyp stone coral (LPS)
  • Small polyp stone coral (SPS)
Recommended
  • Microalgea (Eg. spirulina)
  • Macroalgea (Eg. seaweed / nori)
  • Small crustaceans (Krill, mysis, artemia...)
  • Larger crustaceans (Shrimp, crabs...)
  • Other invertebrates
  • Sponges

High water quality

This species demands a high water quality.

Amongst other things it means, that water must be properly oxygenated.

Can nibble at clams

This species sometimes nibbles at clams including Tridacna species.

Frequent feeding

This fish requires feeding several times a day, especially when newly added.

When the fish can find its natural food in the aquarium it requires less frequent feeding. 

Well established aquarium with algae

These fish should be kept in a well run aquarium where they can "graze" algae from rocks and stones.

If there are insufficient algae on the rocks, it is important to feed more frequently and supplement with algae rich food e.g. Spirulina. 

Acclimitises best as a juvenile

This species will better acclimatize to the aquarium`s condition if introduced, when young.

Very small individuals can be very delicate.

Requires a varied diet

This species must be fed with an appropriately varied diet.

Requires plenty of space for swimming.

This species revels in swimming and requires an aquarium with ample space.

Hermaphroditic

This species can change gender from female to male.

When a male is needed, a female changes sex and takes on the role.

Initially shy

This species can be very shy when first introduced into a new aquarium.

More aggressive fish can be introduced after this species has acclimatized.

Hiding places

This species needs good hiding places, for example, between live rocks.

Can coexist as a pair

They can live as a pair provided they are introduced simultaneously.

Grunting sounds

This species can make a grunting sound when it feels threatened for example.

Refuses to eat at first

This species can refuse to eat when newly introduced.
Normally however, they begin to eat within about a week, but it's advantageous if they can find their own food in the aquarium.

Tips for keeping Angelfish

It is possible to keep various different sizes of Angelfish in the same aquarium, but it means that one must choose species with care and that the conditions in the tank are optimum.

Here are some suggestions to increase the chances of success:

Choice of species
It is important not to choose species that are too similar, the greater the variance, the larger the chance of success. It is also advantageous to choose fish of different sizes. Two young Angelfish of the same same size and pattern for example are a bad idea. One should of course avoid the most aggressive species.

Order of introduction
It is a good idea to make a wishlist and choosing the order so, that the least aggressive are introduced first. When adding similar sized Ange fish it works best if they are introduced simultaneously.

Space
There should be enough space in the aquarium, but it is difficult to give specific advice. Of course there are exceptions to the table below as to just how big a tank should be in order to stand a good chance of success. Space itself is not enough, there should also be sufficient hiding places so the fish do not have to fight over these.

100 gal (400 liters): Several small Angelfish (<15cm) can live together.

240 gal (900 liters): Several medium Angelfish (< 20cm) can live together.

400 gal (1500 liters): Several large Angelfish (<25cm) can live together.

Food and water quality
It is always helpful to give the fish a varied diet, so they can withstand the occasional stress situation when for example new fish are introduced. Water quality must also be very high, so that the fish do not get stressed for that reason either.

Corals suitable for an aquarium with Angelfish

It can be a challenge to keep corals together with Angelfish, since the latter eat most soft corals and LPS. Especially Zoathus are swiftly eaten by the larger species.

It is however possible to build up a mixed coral aquarium with Angelfish. If some of the following corals are choosen there is a good chance the Angelfish will leave them alone; Hammer corals, Bubble corals, Star polyps, Disc anemones and others.
Most of the SPS corals can be kept with Angelfish.

Can be aggressive

This species can be aggressive when kept together with fish that are very similar, or if they are not provided with adequate space.

Description

When young these fish are black with white and blue markings.

Genus description (Pomacanthus)

The Pomacanthus genus of Angelfish, is extremely impressive with their beauty of colours and patterns. They live mostly on most sponges, but also soft corals, tunicates and macroalgae found naturally.

There is typically rather a large difference in the appearance between juvenile and adult.

When properly fed, these fish can grow fast and become very large. In captivity, it can take well over a week for these fish to start feeding. This, because they are not used to catching their own food in the aquarium. It is best to feed them little and often, 4/5 times daily.

As the feeding indications suggest, these fish are not reef safe, but if one chooses the corals with care, it is possible to keep them together in a aquarium.
One may obtain a species specific preparation containing sponges to meet nutritional needs of some species. Thier diet should include algae based foods, i.e. nori seaweed, spirulina, or similar.

Pomacanthus species can be very aggressive, but not to the same degree as the Holacanthus. Thus in a tank with shyer species it is best to add a Pomacanthus last.

They must also not be kept together with Lionfish, Seahorses, Scorpionfish or similar, as they might be nibbled.

Family description (Pomacanthidae)

Angelfish (Pomacanthidae) are known as some of the most colourful and impressive fish on the reef.

Many species are not reef safe, as they especially target the soft corals and LPS. But by choosing your corals carefully, or by getting specific species of Angelfish, they can be kept in coral aquariums.

There are Angelfish suitable for most aquarium sizes, from Dwarf Angelfish which are well suited to smaller aquaria, to the larger of the species which can be impressively displayed in a larger aquarium.

The demands of the individual species can vary widely. Some are food specialists and require therefore special food, while for others can be difficult to acclimatize, as they live in deep water in the wild. It is recommended that one has a reasonably good knowledge of the different types of food and of treatments of illnesses, if one wishes to keep the larger species.

FishBase

Aquarium trade Yes
Distribution Indo-Pacific: Red Sea and East Africa to the Hawaiian, Line and Tuamoto islands, north to southern Japan and the Ogasawara Islands, south to the Great Barrier Reef, New Caledonia, and the Austral Islands (Ref. 33390). Not found in Easter Island, Rapa an
English common names Imperial angelfish, Emperor angelfish
Danish common names Ægte kejserfisk
German common names Kaiserfisch
French common names Poisson-ange empereur, Poisson ange impérial

References and further reading

About references

Niels K. 2014. Private conversation - saltvandsforum.dk - (Danish)
Scott W. Michael. 2004. Angelfishes and Butterflyfishes (Reef Fishes Series Book 3) - TFH Publications / Microcosm Ltd. - (English)
Bob Fenner. Marine Angelfishes, Family Pomacanthidae - Wet Web Media - (English)
Bob Fenner. The Best Angelfishes For Marine Aquarium Use - Wet Web Media - (English)
Bob Fenner. The Ultimate Angelfish Aquarium; An amazing and challenging collection of marine angelfishes - Wet Web Media - (English)
Collection of links to additional information - Wet Web Media - (English)
Reef Central. 2009. Keeping more than one emperor angelfish together - (English)

Froese, R. and D. Pauly. Editors. 2014. FishBase. World Wide Web electronic publication. www.fishbase.org, version (08/2014).

Tags

hermaphroditic, herbivore, algae eater, docile shy, pair couple, eats tridacna, angel, tag_kejser
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