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.

---

Common name: harlequin sweetlips

Synonyms and Other Names: spotted sweetlips

Taxonomy: available through www.itis.gov

Identification: This species goes through a dramatic change in coloration and spotting pattern as it grows. Juveniles are brown with 7 large dark-edged white spots or bars on the head and body (Randall 2005). The caudal fin is deeply forked with broad rounded lobes, each white with a large brown spot (Randall 2005). By contrast, the adults are pale green dorsally with numerous close-set black spots on the head and body and uniformly gray ventrally up to the pectoral fin with a slightly forked caudal fin (Randall 2005).

Size: This species can grow to 60 cm standard length (Randall et al. 1997).

Native Range: Harlequin sweetlips is native in the Indo-Pacific Ocean from the Maldives and Mauritius, north to the Ryukus Islands, south to the Great Barrier Reef, and west to Tonga (Myers 1999, Randall 2005).

Interactive maps: Point Distribution Maps

Ecology: Harlequin sweetlips is common on coral reefs at depths 1-30 m (Myers 1999). Adults are solitary and shelter during the day under ledges or tabular/table corals (Myers 1999). The colorful juveniles swim with their heads angled down while excessively undulating their fins. This behavior could be mimicking unpalatable flatworms or nudibranchs offering some protection from predators (Randall and Emery 1971). This species feeds on crustaceans, mollusks, and other fishes (Myers 1999).

Means of Introduction: Probable aquarium release.

Status: Unknown.

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. A study by Kerry and Bellwood (2016) found this species to be moderately competitive for tabular structure space on a coral reef. Non-native large individuals could displace native fishes from this finite shelter resource.

Remarks: This species is susceptible to over-collection in native range for the aquarium trade due to the demand for colorful juveniles (Dee et al. 2019). It could be at an increased risk for aquarium release as it achieves a large adult size and more modest coloration with maturity.

References: (click for full references)

Dee, L.E., K.A. Karr, C.J. Landesberg, and D.J. Thornhill. 2019. Assessing vulnerability of fish in the U.S. marine aquarium trade. Frontiers in Marine Science 5:527.

Kerry, J.T., and D.R. Bellwood. 2016. Competition for shelter in a high-diversity system: structure use by large reef fishes. Coral Reefs 35:245–252.

Myers, R.F. 1999. Micronesian reef fishes: A field guide for divers and aquarists. Coral Graphics, Guam, USA.

Randall, J.E. 2005. Reef and Shore Fishes of the South Pacific: New Caledonia to Tahiti and the Pitcairn Islands. University of Hawaii Press, Honolulu, Hawaii, USA.

Randall, J.E., and A.R. Emery. 1971. On the resemblance of the young of the fishes Platax pinnatus and Plechtorhynchus chaetodontoides to flatworms and nudibranchs. Zoologica 56:115–119.

Randall, J.E., G.R. Allen, and R.C. Steene. 1997. Fishes of the Great Barrier Reef and Coral Sea. University of Hawaii Press, Honolulu, Hawaii, USA.

Reef Environmental Education Foundation (REEF). 2008. Exotic species sighting program and volunteer database. World Wide Web electronic publication. www.reef.org, date of download 10. Mar. 08.

Other Resources:

Author: Brown, M.E., and Schofield, P.J.

Peer Review Date: 8/7/2020

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.