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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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Common name: Moorish Idol

Synonyms and Other Names: Chaetodon cornutus (original combination); Zanclus canescens (synonym)

Taxonomy: available through www.itis.gov

Identification: The Moorish idol is the only species in the Family Zanclidae.  Dorsal spines VI-VII; dorsal soft rays 39-43; anal spines III; anal soft rays 31-37.  The dorsal spines are elongated into a whip-like filament.  The body is deep and strongly compressed, with three wide black and two pale yellow bars.  The protruding, tubular snout has a yellow saddle across the top and contains long, bristle-like teeth.  Distinctive black, yellow and white coloration (see photo above).  Short horn-like projections above the eyes. 

Somewhat similar to the butterflyfishes Heniochus acuminatus (false Moorish idol; poor man's Moorish idol) and Heniochus diphreutes (pennant butterflyfish).

Size: 29 cm TL

Native Range: Wide-ranging in the Indo-Pacific and tropical Eastern Pacific, from East Africa to Micronesia, Hawai’i, Polynesia, México, and the Galápagos Islands.  From Randall (2005), Galván-Magaña et al. (1996), and Allen et al. (2003).

Interactive maps: Point Distribution Maps

Ecology: This species occurs in a variety of hard-bottomed habitats, from turbid harbors to reef flats and seaward reefs (Myers 1999).  Usually it occurs in small groups, but it can form large schools of >100 individuals (Myers 1999).  The Moorish idol feeds on algae, sponges and other invertebrates.  Larvae spend a long time in the plankton before metamorphosing at 40-75 mm TL (Burgess and Axelrod 1973; Myers 1999). 

Means of Introduction: Probable aquarium release.

Status: Reported from Florida.

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.

Remarks: Although present in the aquarium trade, the Moorish Idol is notoriously difficult to keep and generally does not do well in captivity.  Its high mortality rate in captivity has lead to import restrictions in some European countries (e.g., Germany). 

References: (click for full references)

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.

Burgess, W. and H. R. Axelrod.  1973.  Pacific Marine Fishes.  Book 1.  T. F. H. Publications, Inc., Ltd.

Galván-Magaña, F., L. A. Abitia-Cárdenas, J. Rodríguez-Romero, H. Pérez-España and H. Chávez-Ramos.  1996.  Systematic list of the fishes from Cerralvo Island, Baja California Sur, México.  Ciencieas Marinas 22: 295-311.

Myers, R. F.  1999.  Micronesian Reef Fishes.  A Field Guide for Divers and Aquarists.  Coral Graphics, Davie Florida.

Randall, J. E.  2005.  Reef and Shore Fishes of the South Pacific.  New Caledonia to Tahiti and the Pitcairn Islands.  University of Hawai’i Press, Honolulu.

The Reef Environmental Education Foundation (REEF). 2008. Exotic Species Sighting Program and Volunteer Survey Project Database, accessed March 10, 2008.

Other Resources:

Author: Schofield, P.J.

Peer Review Date: 4/27/2009

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.