Blue Spine Unicorn,
Naso unicornis

Photos courtesy of Dr. Jared Nabeta

Common Name: Blue Spine Unicorn, Unicorn Tang
Scientific Name: Naso unicornis
Size: 24 inches in the wild, much less in captivity.
Distinguishing Features: Blue lips and peduncular spines. Long horn in adults. Long tail streamers in adult males.
Origin: Red Sea to Hawaiian Islands, Northern Honshu to New South Wales
Natural Habitat: This large fish frequents inshore reefs and shallow waters.
Feeding Requirements: These fish are relatively easy to feed. They require a diet rich in plant and animal matter. They will accept flakes, frozen or freeze-dried foods and will also graze nuisance algae from the aquarium décor.
Difficulty Rating:
(1 = easy - 5 = hard)
For the advanced aquarist with a large tank. I rate this fish a "3."
Aggressiveness Rating:
(1 = shy - 5 = nasty)
Very peaceful as are most Naso species, but certainly not shy. I rate this fish a "2."
Captive Requirements: These fish do best in established reef tanks. Large amounts of live rock for grazing are preferred. Standard reef tank parameters are optimal. A tank of at least 300 gallons is necessary to prepare for their potentially large adult size. Once acclimated, they are very hardy and quite disease resistant. They will live many years in captivity.
Optional Requirements: These fish will readily accept supplemental feedings of macro or hair algae from a refugium. They also enjoy sheets of dried nori clipped to the aquarium glass.
Reef Tank Compatibility: Yes. They are best kept in reef conditions with lots of open water.
Notes: Nasos are my favourite genus of fish. The Blue Spine Unicorn is probably the most common of the Naso species in the aquarium trade. This is a very beautiful fish once it reaches adulthood. It’s purpley-blue lips and spine stand out against the aquarium background. As with all Nasos this is a very friendly and intelligent fish.
I am always surprised to see this large fish so close to shore in the wild. They are seen both solitary and in schools of juveniles and large adults. Their magnificent streamers and horns make it a must have for my aquarium.
Further Reading: Surgeonfishes, Rabbitfishes and Their Relatives by Rudi H. Kuiter and Helmut Debelius.

Note: All of the above information has been compiled from various sources and should be used as a guideline, not a hardfast rule. Use caution when selecting animals for your own tank and research as much as possible before purchasing any animals. Remember that certain corals and fish are very hard to keep if their special requirements are not met. The information contained here is to help you make an informed decision. The author assumes no responsibility for any consequences that may arise from the use of this information.

Fish Profile: Blue Spine Unicorn, Naso unicornis by Dr. Jared Nabeta -