Blue ring angelfish (Pomacanthus annularis) care guide

Group
Marine fish
Other names
Annularis angelfish, Blue king angelfish
Family
Pomacanthidae (marine angelfishes)
Origin
Indo-West Pacific, East Africa to New Caledonia and southern Japan; coastal rocky and coral reefs, caves and wrecks, 3–30 m
Water
saltwater
Maximum size
30 cm
Temperature
24–27°C
pH
8.1–8.4
Hardness
Salinity SG 1.020–1.025
Minimum tank
1000 litres
Care level
intermediate
Temperament
semi_aggressive
Reef safe
no

Care

Needs a large, long tank with plenty of open swimming space plus caves and overhangs in the rockwork. The minimum tank size of about 1000 litres is our own estimate from the adult size and habits, not a figure from the sources. No species-specific water figures are given in the sources, so the values here are general marine aquarium guidance rather than figures for this fish: 24–27 °C, pH 8.1–8.4 and a specific gravity of 1.020–1.025 (a fish-only system suits it). Keep conditions stable, with low nitrate and good oxygenation. Usually seen in pairs. In the wild a male holds a territory with several females. Can be territorial towards other angelfish. Adults are brown with curved electric-blue lines and a blue ring above the gill cover; juveniles are dark with pale blue and white vertical lines. The list gives 30 cm as the maximum size, but the Wikipedia article gives up to 45 cm, so plan for a fish that may exceed 30 cm. Infrequently seen in the aquarium trade. Its IUCN Red List category is not stated in the article. Selling: our policies require the adult size and long-term tank needs to be stated clearly in the listing. Large fish must travel by a specialist live-animal courier (see the Livestock shipping guide). Sources: Wikipedia, List of marine aquarium fish species (en.wikipedia.org/wiki/Listofmarineaquariumfishspecies); Wikipedia (en.wikipedia.org/wiki/Pomacanthusannularis). Checked October 2026.

Diet

Omnivore. In the wild adults eat sponges, tunicates, filamentous algae and zooplankton. In the aquarium offer a varied diet several times a day: angelfish preparations containing sponge, frozen mysis and krill, marine algae (nori) and spirulina-based foods.

Breeding

Marine angelfish are pelagic broadcast spawners: a pair rises into the water column, usually around dusk, and releases eggs and sperm together. All fish start as females and some later become males (protogynous hermaphrodite). Not routinely bred in home aquaria.

Compatibility and tank mates

Not reef safe: it grazes sponges and tunicates and will pick at stony and soft corals, clam mantles and other sessile invertebrates. Best in a fish-only system with live rock. Keep one large angelfish per tank unless the system is very large; add it after more peaceful fish and alongside robust tankmates such as tangs, larger wrasses and triggerfish of similar size. Avoid small, slow or timid fish.

Last updated 8 October 2026. Community-edited care guide on Aquatic-Auctions.

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