Knothead Parrotfish, Chlorurus oedema (Snyder 1909)

A Knothead Parrotfish, Chlorurus oedema, from Taiwan - ASIZP0060722. Source: Fish Database of Taiwan / License: CC BY Attribution-Noncommercial

A dark bluish to almost black parrotfish with a pale blue margin on the dorsal, anal and pelvic fins, a pronounced hump on the head of adults and contrasting whitish dental plates.

The presence of the Knothead Parrotfish in Australia is yet to be confirmed. Its distribution overlaps with that of the Raggedfin Parrotfish, and the two species may be have been confused. The tail of the Knothead Parrotfish is rounded without 'ragged' fin rays.

Cite this page as:
Dianne J. Bray, Chlorurus oedema in Fishes of Australia, accessed 26 Nov 2022,

Knothead Parrotfish, Chlorurus oedema (Snyder 1909)

More Info


Although the Knothead Parrotfish is recorded in Australia from the Houtman Abrolhos (28°30'S) to the Dampier Archipelago (20°28'S), Western Australia, the presence of this species is yet to be confirmed. The species occurs elsewhere in the tropical, west Pacific.


Meristic features: Dorsal fin IX, 10; Anal fin III, 9; Pectoral fin 15; Medium predorsal scales 3-4; scale rows on cheek 2. 
Head with a hump, right above eye and vertically abrupt to snout. Cheek with 3 scale rows (upper and middle rows 5, lower 1 or 2).

Species Citation

Callyodon oedema Snyder, 1909, Proc. U. S. Natl Mus. 36(1688): 603. Type locality: Naha, Okinawa.


Dianne J. Bray

Knothead Parrotfish, Chlorurus oedema (Snyder 1909)


Allen, G.R. & Erdmann, M.V. 2012. Reef fishes of the East Indies. Perth : Tropical Reef Research 3 vols, 1260 pp.

Bellwood, D.R. 1994. A phylogenetic study of the parrotfishes family Scaridae (Pisces: Labroidei), with a revision of genera. Records of the Australian Museum, Supplement 20: 1-86.

Bellwood, D.R. 2001. Scaridae. pp. 3468-3492 in Carpenter, K.E. & Niem, T.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 6 pp. 3381-4218.

Choat, J.H., Carpenter, K.E., Clements, K.D., Russell, B., Rocha, L.A., Myers, R., Lazuardi, M.E., Muljadi, A., Pardede, S. & Rahardjo, P. 2012. Chlorurus oedema. The IUCN Red List of Threatened Species. Version 2014.3. . Downloaded on 05 September 2014

Comeros-Raynal, M.T., Choat, J.H., Polidoro, B., Clements, K.D., Abesamis, R., Craig, M.T., Lazuardi, M.E., McIlwain, J., Muljadi, A., Myers, R.F., et al.. 2012. The likelihood of extinction of iconic and dominant components of coral reefs: the parrotfishes and surgeonfishes. PLoS ONE

Lieske, E. & Myers, R. 1994. Collins Pocket Guide. Coral reef fishes. Indo-Pacific and Caribbean including the Red Sea. Harper-Collins, London, U.K.

Smith, L.L., Fessler, J.L., Alfaro, M.E., Streelman, J.T. & Westneat, M.W. 2008. Phylogenetic relationships and the evolution of regulatory gene sequences in the parrotfishes. Molecular Phylogenetics and Evolution 49: 136-152.

Snyder, J.O. 1909. Descriptions of new genera and species of fishes from Japan and the Riu Kiu Islands. Proceedings of the United States National Museum 36(1688): 597-610

Westneat, M. W. & Alfaro, M.E. 2005. Phylogenetic relationships and evolutionary history of the reef fish family Labridae. Molecular Phylogenetics and Evolution 36: 370–390.

Quick Facts

CAAB Code:37386033

Biology:Able to change sex

Conservation:IUCN Least Concern

Depth:1-50 m

Habitat:Reef associated

Max Size:42 cm TL

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CAAB distribution map