Naso unicornis   (Forsskal,  1775) (Fish)
Organism information awaits expert curation
Class: Actinopterygii

Image copyrights: Mike Pfeil

Size: 70 cm FL (male).

Color: In preserved specimens uniform brownish. In the Keris stage there is a dark band on nape, and about 6 transverse series of dark spots on the body. Dorsal with basal dark spots and more or less distinct oblique dark longitudinal bands.

Height 2.3-2.5, 2.8-3.1 in length with caudal. Head 3.2-4.3, 3.9-5.3 in length with caudal. Eye 3.3-5, 2.1-4.5 in snout, and 1.1-1.4 in the inter orbital space, which is flat but somewhat keeled. First dorsal longest, fin gradually decreasing in height posteriorly. Anal similar to dorsal equal to snout in the young specimen, one eye diameter shorter than distance between eye and corner of mouth in the large one. Ventrals less than half snout in the old specimens, equal to distance between corner of mouth and eye in the juvenile one. Caudal emarginate in the young, lunate and with produced lobes in the adult. In the young specimens the two bucklers on caudal begin to develop, in the old specimen they are large rounded plates with a high triangular pointed keel. Presence of a horn or rostrum. Both caudal lobes prolonged into filaments. Adult males tend to have better developed horn, peduncular spines, and caudal filaments than females of the same size. Caudal fin. Dorsal spines (total): 6; Dorsal soft rays (total): 27-30; Anal spines: 2; Anal soft rays: 27-30.

Dioecious, external fertilization, nonguarders, open water/substratum egg scatterers. Spawn in pairs.

Remarks: Values in above description denote proportions.

Synonym (s)
Acanthurus unicornis (Forsskal, 1775)
(Senior synonym)
Chaetodon unicornis Forsskal, 1775
(Senior synonym)
Naso unicornis (Forsskal, 1775)
(Senior synonym)
Monoceros biaculeatus Bloch and Schneider, 1801
Naso fronticornis Lacepede, 1802
Aspisurus unicornis Ruppell, 1828
Naseus fronticornis Cuvier and Valenciennes, 1835
Harpurus Monoceros Forster Lichtenstein, 1844
Priodon anginosus Bleeker, 1854
Naseus fronticornis Bleeker, 1857
Naseus unicornis Gunther, 1861
Naseus unicornis Klunzinger, 1871
Naseus unicornis Gunther, 1875
Naseus unicornis Day, 1876
Naseus unicornis Macleay, 1881
Naseus unicornis Klunzinger, 1884
Monoceros marginatus Seale, 1901
Acanthurus unicornis Jordan and Evermann, 1905
Acanthurus unicornis Seale, 1906
Acanthurus unicornis Jordan ans Seale, 1906
Acanthurus unicornis Ogilby, 1905
Naseus (tapeinosoma) M. Weber, 1913
Naso unicornis Jordan and Jordan, 1925
Monoceros unicornis Barnard, 1927
Naso unicornis Herre, 1927
Naso unicornis Fowler, 1928
Naso unicornis Fowler and Bean, 1929
Naso unicornis Fowler, 1931
Prionolepis hewitti J. L. B. Smith, 1935
Naso unicornis Smith, 1949
Naseus unicornis Day, 1878

Common Name (s)
• Ammas (Mahl)
• Niggam-mas (Mahl)
• Karukkan (Malayalam)
• Komban Karukkan (Malayalam)
• Long-snouted Unicorn-fish
• Thol kilathi
Economic Importance and Threats
Importance:  Commercial, Dangers
(Fisheries, gamefish, aquarium, Ornamental fish
Causes ciguatera poisoning.)

Habitat:  Bentho Pelagic, Reef Associated
Trophic Level:  Consumer
Prey:  Plants, benthic algae/weeds (Sargassum), zooplankton
Predator:  Caranx melampygus (fish)


• Lakshadweep, Kavaratti Atoll (Lat: 10.55) (Long: 72.63) INDIA (Record: 01/1991-06/1992)
• Lakshadweep, Agatti INDIA
• Lakshadweep, Bangaram INDIA
• Lakshadweep, Kavaratti INDIA
• Lakshadweep, Minicoy INDIA
• Lakshadweep INDIA
• Red Sea
• Tamil Nadu, Gulf of Mannar INDIA
• Lakshadweep, Kavaratti Island (Lat: 10.56) (Long: 72.95) INDIA (Record: 03/1954)
• Andaman and Nicobar Islands, Mahatma Gandhi Marine National Park INDIA
• Lakshadweep Islands INDIA (Record: 11/1993-01/1997)
• Lakshadweep, Minicoy Island (Lat: 8.11) (Long: 73.3) INDIA

Literature Source(s)
  • Anand, PEV and Pillai, NGK (2005) Community organization of coral reef fishes in the rubble sub-habitat of Kavaratti Atoll, Lakshadweep, India Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin, India 47(1) 77-82 Available at - NIO, Goa
  • Society for the Management of European Biodiversity Data (2009) World Register of Marine Species (WoRMS) Available at -
  • Julian rocks Available at -
  • Anand, PEV and Pillai, NGK (2003) Habitat distribution and species diversity of coral reef fishes in the reefslope of the Kavaratti atoll, Lakshadweep, India Journal of the Marine Biological Association of India The Marine Biological Association of India, Cochin 45(1) 88-98 Available at - NIO, Goa
  • Froese, R and Pauly, D (2000) Fishbase 2000: Concepts, design and data sources ICLARM 344 pp Available at -
  • Beaufort, LF and Chapman, WM (1951) The fishes of the Indo-Australian Archipelago A. J. Reprints agency, Karol Bagh, New Delhi 9 484 pp Available at - NIO, Goa
  • Jones, S and Kumaran, M (1980) Fishes of the Laccadive Archipelago The Nature Conservation and Aquatic Sciences Service, Trivandrum, Kerala 760 pp Available at - NIO, Goa
  • Fischer, W and Bianchi, G (Eds.) (1984) FAO species identification sheets for fishery purposes. Western Indian Ocean; (Fishing area 51). FAO, Rome 1 Available at -
  • Dr. Kumaraguru, AK (2000) Studies on socioeconomics of Coral Reef resource users in the Gulf of Mannar coast, South India Centre for Marine and Coastal studies School of Energy, Environment and Natural Resources Madurai Kamaraj University, Madurai, India Available at -
  • Jones, S. (1969) Catalogue of fishes from the Laccadive Archipelago in the reference collections of the Central Marine Fisheries Research Institute. Bulletin of Central Marine Research Institute CMFRI, Cochin 8 1-35 Available at -
  • Balan, V (1958) Notes on a visit to certain islands of the Laccadive Archipelago, with special reference to fisheries Journal of the Bombay Natural History Society Bombay Natural History Society 55 (2) 297-306 Available at -
  • Murty, VS (1996) Marine ornamental fishes of India Proceedings of the Seminar on Fisheries - A Multibillion Dollar Industry, Madras CMFRI 23-34 Available at -
  • Murty, VS (2002) Marine ornamental fish resources of Lakshadweep CMFRI Special Publication CMFRI 72 1-134 Available at -
  • Jones, S and Kumaran, M (1959) The fishing industry of Minicoy Island with special reference to the tuna fishery Indian Journal of Fisheries Indian Council of Agricultural Research 6 (1) 30-57 Available at -
  • Ghosh, S; Ganeshamurthy, R; Balamurugan, J and Kumar, TTA (2011) Reef fishing- An off season amusement at Lakshadweep Fishing chimes 31(1) 128-130 Available at - NIO, Goa
  • Murty, VS (2001) Ornamental fish resources of Lakshadweep Bulletins of the Geological Survey of India 56 103-111 Available at -
  • Pillai, PKM and Augustine, SK (2000) A code list of common marine living resources of the Indian seas CMFRI Special Publication No.12 CMFRI 1-115 Available at -

Page last updated on:2011-12-07

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