Pomacanthus semicirculatus
Pomacanthus semicirculatus
(semicircle angelfish)
Marine Fishes
Exotic
Collection Info
Point Map
Species Profile
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Carol Cox, Mexico Beach Artificial Reef Association Copyright Info
Pomacanthus semicirculatus (Cuvier in Cuvier and Valenciennes, 1831)
Common name: semicircle angelfish
Synonyms and Other Names: Koran angelfish
Taxonomy: available through www.itis.govITIS logo

Identification: Adults are dusky brownish-green along the anterior and posterior thirds of the body; the center third is a paler yellow-green.  Scales along the flanks are blue at the base.  All fins are edged in blue except pectoral fins; dorsal and anal fins end in filaments.  Mouth is pale yellow.  Blue margins on cheek, spine and gill cover.  Juveniles have a dark blue to black base color, with distinct narrow white and blue stripes.  The stripes are more vertical near the head (i.e., anteriorly), and semicircular towards the posterior of the body.  Juveniles intergrade to adult coloration at 8 to 16 cm TL.  Grows to 35 cm TL.  Dorsal fin XIII (20-23), anal fin III (18-22); pectoral rays 19-21.  From Allen et al. (1998 and 2003), Randall et al. (1996) and Randall (2005).

Similar species:  Intermediate gray angelfish (Pomacanthus arcutatus) lacks blue margins on opercle and opercular spine, and lacks markings in tail.  Juvenile queen angelfish (Holacanthus ciliaris) and blue angelfish (Holacanthus bermudensis) have bright blue body bars. Juvenile French angelfish (Holacanthus paru) and gray angelfish (Holacanthus arcuatus) have bright yellow body bars on black body.
Size: to 35 cm TL
Native Range: Widely dispersed in the Indo-West Pacific, from East Africa to Palau and Fiji; southern Japan to New South Wales, Lord Howe Island and New Caledonia.  From Allen et al. (1998), Randall et al. (1996) and Randall (2005).

Interactive maps: Point Distribution Maps

Nonindigenous Occurrences: In Florida, the semicircle angelfish has been seen off Boca Raton (1999), Ft. Lauderdale (1999), Pompano Beach (2004), Deerfield Beach (2001), Delray Beach (2002), Boynton Beach (2001), and Palm Beach (2012, 2014).  Each observation was of one individual.  The species has also been observed in Oahu and the Big Island, Hawai’i (Mundy 2005).

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Pomacanthus semicirculatus are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
FL199920142Florida Southeast Coast; Floridian
HI200120111Hawaii

Table last updated 3/28/2025

† Populations may not be currently present.
Ecology: The species is found on protected coral reefs with well-developed coral growth to depths of 40 m.  Juveniles are secretive and difficult to approach.  Adults feed mainly on sponges, tunicates and algae.  From Allen et al. (1998 and 2003) and Randall (2005).
Means of Introduction: Probably aquarium release.
Status: Reported from Florida and Hawaii.
Impact of Introduction: The impacts of this species are currently unknown, as no studies have been done to determine how it has affected ecosystems in the invaded range. The absence of data does not equate to lack of effects. It does, however, mean that research is required to evaluate effects before conclusions can be made.
References: (click for full references)

Allen, G. R., R. Steene and M. Allen.  1998.  A Guide to Angelfishes and Butterflyfishes.  Odyssey Publishing/Tropical Reef Research, Perth.

Allen, G., R. Steene, P. Humann and N. Deloach.  2003.  Reef Fish Identification.  Tropical Pacific.  New World Publications, Inc., Jacksonville, Florida and Odyssey Publications, El Cajon, California.

Mundy, B. C.  2005.  A checklist of the fishes of the Hawaiian archipelago.  Bishop Museum Bulletins in Zoology, Number 6.

Reef Environmental Education Foundation (REEF).  2008.  Exotic species sighting program. on-line: http://www.reef.org/exotic.

Randall, J. E.  2005.  Reef and Shore Fishes of the South Pacific.  University of Hawaii Press, Honolulu.

Randall, J. E., G. R. Allen and R. C. Steene.  1996.  Fishes of the Great Barrier Reef and Coral Sea.  Second Edition.  University of Hawaii Press, Honolulu, Hawaii. 

Other Resources:
FishBase Summary
Author: Schofield, P.J.
Revision Date: 9/14/2020
Peer Review Date: 1/9/2013

Citation Information:
Schofield, P.J., 2025, Pomacanthus semicirculatus (Cuvier in Cuvier and Valenciennes, 1831): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=2296, Revision Date: 9/14/2020, Peer Review Date: 1/9/2013, Access Date: 3/28/2025

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.

Disclaimer:

The data represented on this site vary in accuracy, scale, completeness, extent of coverage and origin. It is the user's responsibility to use these data consistent with their intended purpose and within stated limitations. We highly recommend reviewing metadata files prior to interpreting these data.

Citation information: U.S. Geological Survey. [2025]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [3/28/2025].

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Disclaimer:

The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.



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