Last Update : Sunday 14 October, 2001 1:10 PM

		Illust : Anuwat Saisaeng

White-margin unicorn fish
Scientific name	Naso annulatus
Common name	White-margin unicorn fish
Size	60 centimeters
Dispersion	Andaman sea. Very few in the Gulf of Thailand.
Area found	Pelagic fish. Found in clear water area.
Depth	5 – 5- meters
Feed on	Animal plankton in the middle of water.
Situation	Can be found but not very much, usually in a group of 1- 3. Cannot be found in a large school any more.
Conservation	Not eaten or kept in the aquarium. Quantity reduced by an indirect effect of fishing.
Fish Tip	Peculiar fish for beginners. Those who have not seen fish with a horn will surely be frightened.

          Here comes the peculiar fish according to the request of our fan. She went diving at Surin Island and met this one. So, she wants to know what kind of a fish has a horn.

          We call them unicorn fish. They are in the same Family Acanthuridae as surgeon fish. I used to write about this group when blue surgeon fish was our Fish of the Week. Fishes in this Family are divided into 3 sub-groups according to barbs at caudal peduncle. There are 50 species that have 1 barb. Those are in Sub-Family Acanthurinae, the same as surgeon fish. Those who have 2 barbs filing are classified in Sub-Family Nasinae, the same as unicorn fish. There are 15 species in this Sub-Family. All of them are in Genus Naso.

          It is not necessary that all unicorn fish have a horn. Some have protruding forehead instead of a horn. The horns are also short and long differently. For Mister Tee’s drawing this time, he has a reasonably long horn. Some types have longer horn than this.

          There are about 6 species of unicorn fish found in Thailand. (According to my own observation. There might be more.) He is not easily found, yet nor so difficult. If you go diving in Surin or Similan Islands for 3 days, either shallow water or deep water dives. Look out to the blue water mass, you will find this kind of fish swimming alone or in a group of 2 – 3. We do not usually meet a large group because the population has reduced. In other countries I met tens of them swimming together, making me afraid of being thrusted.

          Unicorn fish looks for food in the daytime. At night, each one goes to find a place to sleep. Some ducked under a coral. Some move slowly on the floor in the deep.

          The horn has no fighting function. They use barbs at the caudal peduncle to fight the enemy instead. Also, this kind of fish is relatively large in size and swims quickly. Usually there is no predator in the daytime. However, during the night barracuda or shark can take them as food. That is normal.

          The horn is not used as food catching tool either. Many people might understand that unicorn fish chase after smaller fishes and stab them to death before shaking them loose and eat them, using the horn like a barbecue skewer. That is not the case.

          The horn of unicorn fish is found in large fish. What it is there for, I do no know.

You are invited to vote for Fish of the Week

Copyright © 1999-2001 TalayThai.com All right reserved.