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Pomacanthus annularisBlue ring angelfish(Also: Ringed angelfish)

By Abigail Brackney

Geographic Range

Pomacanthus annularis live in the Indo-Pacific region ranging from Sri Lanka to the Solomon Islands and from the Philippines to the northern tip of Australia. Normally this range is from 25 degrees north to 25 degrees south (Agbayani, 2002; Heemstra, 1986).

Habitat

P. annularis is a tropical, marine (salt water) fish that lives around coastal rocky coral reefs and other hard bottom coastal areas. In their natural habitat the adults are normally found from 5-15 meters in depth, but as far down as 30 meters. The juveniles are usually at the upper range of the adults and sometimes are in even shallower water. When kept as aquarium fish, optimal temperature is 26 degrees Celsius with a pH of 8 and lots of light.

The adults of the genus Pomacanthus are normally haremic; one male defends a territory with two to five females living with the male. They are usually found alone or in pairs in caves in the rocky/coral oceanic bottom (Steen, 1978; Tullock, 1996; Agbayani, 2002).

  • Range depth
    3 to 30 m
    9.84 to 98.43 ft
  • Average depth
    5-15 m
    ft

Physical Description

Adult P. annularis are a dark orange to brown color with white caudal fin, grow up to 12 inches in length, head to caudal fin and are monomorphic between sexes. Soft dorsal spine rays, numbering 20-21 are at times longer than normal so that they extend further than the rest of the dorsal spine rays. There are also 13 dorsal spines with the dorsal fins being continuous, three anal spines and 20 soft anal rays (Agbayani, 2002). Adult bluering angelfish have blue, horizontal curved lines that extend from the back of the head/pelvic fin area to the dorsal and caudal fins. Also there are two blue stripes that cross the face, one through the eye and the other below. Finally, the blue ring (where it gets its common name) is above and behind the operculum (Agbayani, 2002; Nelson, 1994; Thresher, 1984; Heemstra, 1986).

Members of the family Pomacanthidae were classified until recently in a family with butterfly fishes because they share many features "such as deep compressed bodies, ctenoid scales which extend out onto the median fins, a small mouth with brush-like teeth. But differ from butterfly fishes, however, in having a long spine at the corner of the preopercle (also smaller spines on the preopercle, opercle, and preorbital) (Allen, 1994). Other differences include the presence of a snout in angelfish and a pelvic axillary process (Helfman et al., 1997).

  • Range length
    20 to 45 cm
    7.87 to 17.72 in
  • Average length
    30.5 cm
    12.01 in

Development

The larvae hatch at sunset the day after the courtship ritual of the parents and swim with the plankton for a month before developing into juveniles. This type of fish is not able to reproduce well in captivity because the larvae are unable to survive. The fish are considered protogynous hermaphrodites, meaning at the beginning of life all are females. Then as development continues the larger fish become males (Tullock, 1996).

Also during development a drastic change occurs in the coloration patterns of juvenile P. annularis to the adult. The juveniles start out with alternating, vertical blue and white stripes on a black background. This coloration pattern is similar to all large angelfish and P. annularis juveniles often are misidentified as P. chrysurus. However, the caudal fin is transparent in bluering angelfish but is yellow in P. chrysurus. Then as they mature into adults, the vertical blue and white stripes disappear, the caudal fin whitens, and the background becomes a dark orange to brown. Horizontal, curved blue lines also appear and run from the back of the head/pelvic fin area to the caudal and dorsal fins (Agbayani, 2002; Heemstra, 1986).

Reproduction

For members of the genus Pomacanthus, spawning normally begins with the onset of dusk and is thought to be triggered by the decrease in light. However it is not known whether there is a correlation between time of year or with the lunar cycle and the onset of spawning in angelfish. The adults have a courtship ritual that ends in the male and female slowly swimming toward the surface of the water and releasing eggs and sperm. The larvae then swim with the plankton for a month before continuing development. Spawning is thought to take place between only one male and one female at a time, but males possibly mate with more than one female with in the group (Thresher, 1984; Agbayani, 2002; Tullock, 2002).

  • Range time to hatching
    15 to 24 hours
  • Average time to hatching
    20 hours
  • Parental Investment
  • no parental involvement

Lifespan/Longevity

Some large angelfish, such as the P. annularis have been recorded to live up to 25 years in an aquarium (www.sphyraena.com/library/angelfish.html).

  • Range lifespan
    Status: captivity
    25 (high) years

Behavior

Almost all angelfish, and probably the bluering angelfish, are haremic, which means there is one male defending a territory with two to five females. This territory can be from the size of a bathroom to the size of a two-car garage (Tullock, 1996). They can often be found in caves at night or swimming for food during the day in pairs or alone (Steen, 1978; Agbayani, 2002).

Communication and Perception

Food Habits

P. annularis are omnivorous, eating benthic invertebrates such as zooplankton, sponges, tunicates and coral polyps. Also these fish eat ascidians, algae, weeds, and nektonic fishes (Steen, 1978; Agbayani, 2002).

  • Animal Foods
  • cnidarians
  • other marine invertebrates
  • Plant Foods
  • leaves
  • algae

Economic Importance for Humans: Positive

The bluering angelfish is kept as an aquarium fish and is exported regularly from Sri Lanka (Ceylon) to the US and Europe (Heemstra, 1986; Agbayani, 2002).

Economic Importance for Humans: Negative

None

Conservation Status

Contributors

William Fink (editor), University of Michigan-Ann Arbor.

Abigail Brackney (author), University of Michigan-Ann Arbor.

Glossary

Australian

Living in Australia, New Zealand, Tasmania, New Guinea and associated islands.

World Map

Pacific Ocean

body of water between the southern ocean (above 60 degrees south latitude), Australia, Asia, and the western hemisphere. This is the world's largest ocean, covering about 28% of the world's surface.

World Map

benthic

Referring to an animal that lives on or near the bottom of a body of water. Also an aquatic biome consisting of the ocean bottom below the pelagic and coastal zones. Bottom habitats in the very deepest oceans (below 9000 m) are sometimes referred to as the abyssal zone. see also oceanic vent.

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

coastal

the nearshore aquatic habitats near a coast, or shoreline.

external fertilization

fertilization takes place outside the female's body

fertilization

union of egg and spermatozoan

folivore

an animal that mainly eats leaves.

herbivore

An animal that eats mainly plants or parts of plants.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

native range

the area in which the animal is naturally found, the region in which it is endemic.

omnivore

an animal that mainly eats all kinds of things, including plants and animals

oriental

found in the oriental region of the world. In other words, India and southeast Asia.

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pet trade

the business of buying and selling animals for people to keep in their homes as pets.

piscivore

an animal that mainly eats fish

planktivore

an animal that mainly eats plankton

polygynous

having more than one female as a mate at one time

protogynous

condition of hermaphroditic animals (and plants) in which the female organs and their products appear before the male organs and their products

reef

structure produced by the calcium carbonate skeletons of coral polyps (Class Anthozoa). Coral reefs are found in warm, shallow oceans with low nutrient availability. They form the basis for rich communities of other invertebrates, plants, fish, and protists. The polyps live only on the reef surface. Because they depend on symbiotic photosynthetic algae, zooxanthellae, they cannot live where light does not penetrate.

saltwater or marine

mainly lives in oceans, seas, or other bodies of salt water.

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

tactile

uses touch to communicate

territorial

defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement

tropical

the region of the earth that surrounds the equator, from 23.5 degrees north to 23.5 degrees south.

year-round breeding

breeding takes place throughout the year

References

"Pomacanthidae angelfish" (On-line). Accessed October 20, 2002 at http://www.sphyraena.com/library/angelfish.html.

Agbayani, E. 2002. "Pomacanthus annularis, Bluering angelfish" (On-line). Accessed October 15, 2002 at http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=7902&genusname=Pomacanthus&speciesname=annularis.

Allen, G., P. Robertson. 1994. Fishes of the Tropical Eastern Pacific. Honolulu: University of Hawaii Press.

Heemstra, P., M. Smith, J. Smith. 1986. Smith's Sea Fishes. New York: Springer-Verlag.

Helfman, G., B. Collette, D. Facey. 1997. The Diversity of Fishes. Malden, Mass: Blackwell Science.

Nelson, J. 1994. Fishes of the World. New York: John Wiley and Sons Inc..

Steen, R. 1978. Butterfly and Angelfishes of the World. New York: Wiley.

Thresher, R. 1984. Reproduction in Reef Fishes. Neptune City, NJ: T.F.H. Publications.

Tullock, J. 1996. "Marine Angelfish" (On-line). Accessed October 15, 2002 at http://www.amdareef.com/ho_angel_info.htm.

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