Vlamingi Tangs do not form the unicorn horn that some from this genus have, yet they do develop a rounded prominent snout.  Their bodies have vertical blue lines that break up into smaller blue dots closer to the top and bottom of the body, although they can hide these blue markings if they want to blend into rock work.  These large Naso tangs have tall dorsal and anal fins, and the face is slightly pale, and can be a light tan to brown depending on their mood.  There is a wide blue band that runs from the eye area to the front of their snout along with blue lips!   Being a very big fish that will reach a length of just under 2 feet, 23.6″ to be exact, and they can live to 30 to 45 years (Choat and Axe, 1996).  This pretty specimen is most suitable for a very large show aquarium, so they are best reserved for intermediate aquarists.

The friendly Vlamingi Tang not only gets more beautiful as it gets larger, but has the ability to quickly and dramatically change its color from pale to brilliant to dark, depending on mood or environment.  In the wild they will be a more moderate slate bluish color when swimming in the open ocean, becoming darker as they approach the reef and lighter when they approach a cleaning station. Being able to hide their blue markings completely is quite an advantage for the Vlamingi Tang as they blend into the reef.  When trying to impress a female or indicate anger/ dominance, the male will seem to flash with brilliant metallic blue lines and spots.  As juveniles, they will do you the favor of cleaning algae off of your live rock, but as adults they are basically carnivorous.

Provide your Vlamingi Tang with plenty of room to roam around the tank with lots of spaces between rocks for them to swim between.  Provide live rock with naturally growing algae and mysis, and chopped table shrimp to entice it to eat. Once eating, your “little” guy can be offered a variety of algae-based aquarium fare for its basic diet, along with meaty foods from the mollusk family (saltwater varieties).  Once they get acclimated and become accustomed to aquarium foods they are quite hardy and long lived.  Tanks that are smaller can cause behavioral problems as they become adults.  They will be almost 19″ by the time they are 5 years old, indicating a growth of 3.5 to 4″ per year.  They are quite hardy once acclimated to their home. 

Being a peaceful fish with an amicable nature, it will get along with most other marine fish, except others from their genus and possibly other tangs in general, due to their territorial nature.  Unless you have a huge (hundreds of gallons) system, it is best to house just one tang to a tank.  You can add other tangs that are from a different genus in a tank that is very large, however do this when they are young and all at the same time.  They get along with all fish except very aggressive triggers or fish that can swallow them whole (as juveniles).  Assessors may be too timid due to their large size and swimming habits.  Natural algae growth and lots of little meaty living morsels like copepods and amphipods will be greatly appreciated!  They are nice suited for a reef environment if the corals are glued down due to their bursts of “I just have to be OVER THERE right NOW!!”  A rare specimen may taste the slime that LPS and clams produce, however, this is only done by a hungry tang.  

Tank size should be 180 gallons or more.  The Vlamingi Tang needs a lot of water turbulence rather than a placid aquarium with open areas above coral and rock to swim as they will pace back and forth during the day. They also need rocks/corals to provide some cover and to sleep in at night.  Be sure to provide larger crevices for them to sleep in as they get older.  The lower end of their spectrum of temperature will have more oxygen, which is necessary for this active swimmer.  Tangs love to swim toward power heads to get that water “rush,” so provide at least one area in the tank that they can do this.  The back of the tank is best suited if you have corals and don’t want them blown all over the place.  They will occupy all areas of the tank and it is possible, similar to the Naso Tangs, they may jump, so egg crate that is weighted down, especially once full grown is suggested. 

Scientific Classification


Habitat: Distribution / Background

   The Vlamingi Tang, Naso vlamingii, was described by, Valenciennes, in 1835.  They have a few common names which either bear their species name, vlamingii, or is descriptive of their features and these are Big-Nose Unicorn, Bignose Unicornfish, Scribbled Unicornfish, Surgeonfish, Unicornfish, and Vlaming’s Unicornfish.  Since “Bignose” seems to be more of an insult, maybe we will will stick with the most popular, Vlamingi Tang!

  This species of the Naso genus are found in the Indo-Pacific from east Africa to southern Japan; Line, Marquesans, and Tuamoto Islands; and the southern Great Barrier Reef and New Caledonia.  They prefer deep lagoons and seaward reefs, where they feed on algae alone or in pairs; however, they will swim in larger schools or mid-water aggregations along the upper parts of deep drop-offs and steep slopes to feed on zooplankton during the day.  In their natural habitat they are found at depths down to about 165 feet (50 meters) and are usually within 32 to 65 feet (10 – 20 meters) of the reef where they can quickly retreat if necessary.  They feed on zooplankton, benthic algae and weeds, making them more omnivorous than herbivorous.  

  Vlamingi Tangs are found most often alone or in pairs, only coming together to feed on zooplankton in larger groups during the day.  They are on the IUCN Red List for Endangered Species under Least Concern.


   The Vlamingi Tang or Bignose Unicornfish become quite spectacular as they grow.  They develop their beautiful adult coloring when they reach around 8″ to 10″ in length.  Like the other Naso species they have an elongated body shape with a narrower caudal peduncle, features that distinguish this genus from other Acanthurids. The forehead of the adult Vlamingi forms a bulbous rounded protrusion, much less of a horn than many of other unicornfish, and thought to be more pronounced in males.  They have very tall dorsal and anal fins.

   Adults generally having a grayish-brown color overall with vertical blue lines on the sides and small blue spots along the upper half of the body and down close to the belly. The head, sometimes more of an olive color, has a blue trimmed mouth. There is a blue band running horizontally across the top of the snout just below the eye. The dorsal, anal fin, and caudal fin are beautifully edged in blue.
   Juveniles are less striking, being generally gray and lacking the lines. The top half of the body is a greenish yellow and the area below the pectoral fin is generally white. Areas can change into a brown or olive coloration with hues of gold and blue. The lips are blue and the caudal fin is dark. Juveniles will start to show their adult colors at around 5 inches.  Athough juveniles can be confused with the Elongate Surgeonfish (Naso lopezi), in general the Vlamingi will have darker coloring and the Elongate will be more pale and more on the grayish blue side and the Elongate will not have the blue speckling in the tail fin.
   On each side of the caudal peduncle are two fixed spines or “scalpels” used for defense or dominance. Having one or two fixed blades are what places the Naso genus in the subfamily Nasinae. Caution needs to be exercised when handling surgeonfish as a cut from its scalpel can cause discoloration and swelling of the skin with a high risk of infection. The pain lasts for hours then still ends up having a dull ache. These fish are best captured using a double bag under water, rather than a net.
   The Vlamingi Tang will live for 30 to 45 years (Choat and Axe 1996), and can reach 23.6″ (60 cm) if a male.

Fish Keeping Difficulty

   Once eating, Vlamingi Tangs are hardy and easy to maintain as long as sufficient space is provided. Obtain a specimen that is at least 4″ long as smaller ones rarely adapt to living in captivity. As they attain around 80% of their growth in the first 5 years of life, this means they are growing at a rate of approximately 3 – 4″ per year and will be 19 to 20″ by 5 years old!  They must be housed in a large tank from the beginning. It is best not to purchase small with the idea of “getting a bigger tank” later, as these fish will quickly outgrow a smaller tank. Four feet long is the minimum length for a small specimen, but as this would be quite temporary a six foot or larger aquarium that is two feet front to back is necessary.  Too small of an environment can stunt their growth, cause health issues, and can cause ‘behavior problems’.  A healthy Vlamingi Tang will be swimming the length of the tank during the day. If you see any sulking, hiding behavior, this is an indication of stress. If their reason for sulking is not resolved or they are stressed for too long they may not recover.
   They can handle a wide range of water parameters but will do best in an environment that provides consistency, not only in water conditions and quality, but also in decor and fellow inhabitants. They can be housed in a fish only tank, and as they will not harm corals or invertebrates they are compatible in a reef environment. However because they are clumsy swimmers, they often knock over rocks/ corals so may not be best for a reef.
   Naso tangs are continuous feeders and they need to be provided a proper diet. They are susceptible to nutritional disorders which may cause color loss and LLD (lateral line disease). Supplementing their diet with the addition of vitamin C to their food or adding a vitamin supplement directly to their water can help to avoid or aid in reducing these ailments. They are also susceptible to bacteria resulting from organic buildup which deteriorates water quality. Consequently, they will need vigorous filtration, protein skimming, and regular small water changes.
   Many of the Acanthuridae members are very colorful, active, and attractive to aquarists. But they do not produce as much skin mucus on their bodies as other fish and can be susceptible to diseases such as Marine Ich and Marine Velvet. Surgeonfish are definitely a candidate for quarantine when you first receive them. They can be treated successfully with medical care or copper drugs, but because they have an important microfauna in their digestive system, prolonged or continuous use of a copper treatment is not advisable.
   In the wild a cleaner wrasse (Labroides sp.) will help them by taking parasites from their bodies, however, these wrasses are extremely difficult to sustain in captivity. Alternative fish such as Neon Gobies (Gobiosoma sp.) or cleaner shrimp can help them by providing this cleaning service in the home aquarium.

Foods and Feeding

   The Vlamingi Tang or Bignose Unicornfish omnivores. Fishbase records not only zooplankton but benthic weeds and algae in the stomachs of juveniles and adults, though the ratios seems to change as they age.  Juveniles feed mainly on algae, so your Vlamingi unicornfish will eat more veggies as a juvenile and more meaty foods as an adult.  Adults still need spirulina and other algaes to stay healthy.  
   Being an herbivore when young, the majority of their intake will be vegetable matter and as they grow they will need some meaty foods as well. Provide lots of algae, prepared frozen formulas containing algae or spirulina, frozen brine and mysis shrimp, and flake foods. Japanese Nori or other seaweed can be adhered to the aquarium glass with a vegetable clip. An occasional live rock with micro and macro organisms will be greatly appreciated. Culturing macro algae like chaetomorphia in the tank is also a great idea. Feed 3 times a day in smaller amounts instead of a large quantity once a day. This will keep the water quality higher over a longer time.  As they get older, they feed on zooplankton more often and only need to be fed 2ce a day once they are adults.
   Providing a vitamin supplement (including vitamin C) can help provide for their nutritional needs, and vitamin C can help prevent or reduce Lateral Line Erosion (LLE). This can be done by soaking dried pellets with liquid vitamins, adding vitamins to the food, or adding a liquid vitamin into the water. It is also said that pellets soaked in garlic may help fend off Marine Ich. Some hobbyists also report success with supplemental foods such as previously boiled or frozen zucchini, broccoli, spinach, and leaf lettuce.

Aquarium Care

   The Vlamingi Tang is very active and constantly moving, it will spend a good deal of its time in the open water. They may jump out of an open aquarium, so be sure to have a lid.

Reef tanks:
-Large Tanks 100 gallons and over, once water is aged and stable can be changed 10% bi-weekly to 20% monthly, depending on bioload.

Fish only tanks:*
-Large Tanks 100 gallons and over, once water is aged and stable can be changed 20% to 30% every 6 weeks depending on bioload.

For more information on maintaining a saltwater aquarium see: Saltwater Aquarium Basics: Maintenance. A reef tank will require specialized filtration and lighting equipment. Regular water changes done  bi-weekly will help replace the trace elements that the fish and corals use up.  

*Note:  If this is the ONLY fish in the tank, with no corals or other fish you can get away 20% monthly.

For more information see, Marine Aquarium Basics: Maintenance

Aquarium Setup

   A minimum tank size of 180 gallons (with a minimum length of 6 feet), is needed by the time this tang is 4 to 5″ which is usually the purchase size.  They grow about 3″ a year during their first 5 years, thus reaching over 19″ by the time they are 5 years old.   Keeping them in a smaller tank will mean having to move them within a year.  If your Vlamingi Tang is only 2″ to 3″ then a 75 gallon tank will be fine for about 6 months to a year, no longer!  If the tank is too small, this can stunt their growth, causing health issues along with development of ‘behavior problems’.  Provide an open area on the top part of the tank with no rocks and below add plenty of rocks/ corals to provide some cover and for sleeping. This decor will lend itself to algae growth which these fish will enjoy grazing on, along with the copepods and amphipods they like to eat.  It can be kept under normal lighting conditions in the aquarium, but can also be kept under very bright light as long as some dimly lit spaces are provided.  

     They can handle a wide range of water parameters but will do best in an environment that provides consistency, not only in water conditions and quality, but also in decor and fellow inhabitants.  With that in mind temperatures should be temperatures need to be kept stable and somewhere between 72 – 79° F (23 – 26° C) and pH between 8.1 to 8.4.  All surgeonfish need an aquarium with plenty of aeration and a strong current that they will face into since they love to have water rushing over their gills!  This will help to provide good oxygenation which they need due to their active swimming habits.  They are found at all levels of the tank, and will spend time in the open water constantly moving and grazing.   Tanks will sleep in crevices or caves by spreading their fins and “locking” themselves in at night.

Social Behaviors

   Vlamingi Tangs are quite peaceful and unobtrusive making them an excellent addition to a community aquarium.  Do not house with other Vlamingi Tangs unless you have a 20,000 gallon tank!  They are quite territorial when it comes to their own kind and others from their genus.

The Vlamingi Tang is the most aggressive of this peaceful group of fish, so are a little more able to hold their own in a semi-aggressive tank. They get along with most other marine fish and can be kept with a variety of tank mates including other genus’ of surgeonfish as long as the tank is hundreds of gallons, otherwise, it is best to house just one Naso tang to a tank.  When attempting to keep multiple tangs, they should be similar in temperament and not timid like the Convict Tang.   Adding tangs that are different colors and different genus is best done when everyone is young and all at the same time it a tank that is, as mentioned before, hundreds of gallons.  Though a large aquarium can help alleviate many problems, be aware of the social behaviors of any species you are considering to prevent compatibility problems. Introducing a new surgeonfish into an aquarium that already houses one or more is usually a problem. If it must be done, then change the rock workaround to alleviate any aggression to the “new guy,” since they will be busy reestablishing territories, not defending their own.   A little chasing will occur, and while it usually doesn’t end up in a knock down drag out fight, still keep an eye on the new guy for at least a month.  Again, avoid housing with the more peaceful tangs.

  Although literature states that a rouge tang will nip at large-polyp stony corals, most aquarists to feed their tang properly will not run into this problem.  Don’t confuse picking at corals with them picking at any algae at the base of a stony coral, which was a great service to the coral! large energetic fish and may topple corals while swimming about in fast clips.  

   A few inverts may be at risk, including small snails like stomenella snails and other snails .5” or less, because they eat small snails in the wild.  They will eat copepods and amphipods, but they will not decimate the population.  On a rare occasion, an occasional tang will find the slime that clams produce quite tasty.  While the tang is not biting the clam, the action causes the clam to close often, stressing the clam and eventually, this stress will kill the clam.  This shouldn’t be a problem with a well-fed tang, but since this tang is fine with eating some meaty foods, keep an eye on your clams.

Sexual differences

  Males of the Naso species will be larger, will have a longer horn-like projection on the forehead, and the caudal peduncle will be larger and more pronounced than on the females. Males will also have long streamers that extend from the upper and lower tips of the tail fin.

Breeding / Reproduction

   Vlamingi Tangs spawn in pairs in the open water. When trying to impress a female or indicate anger/ dominance, the male will seem to flash with brilliant metallic blue lines and spots.  A pair will rise to the surface to release their gametes. The eggs are pelagic with an extended larval phase, which probably accounts for the vast distribution of the Unicornfish. 

  Some species of surgeonfish have spawned in public aquariums and there have been a few scattered reports of spawning in home aquariums, but regular spawning and the rearing of the young has not yet been reported.

   For more information on breeding and the development of the fry, see: Marine Fish Breeding: Tangs.

Fish Diseases

   Tangs produce less body slime than other saltwater fish and have been termed “dry skinned” fish by some.  This makes them very susceptible to Cryptocaryon (saltwater ich) and other diseases.  The most common ailments are bacterial diseases, Hole-in-the-Head Disease or Lateral Line Disease, and parasitic infections such as protozoas (including Cryptocaryon), worms, etc.  

   As for treatment, some tangs are sensitive to copper.  To avoid Lateral Line Diseae, avoid using activated carbon, as it has been scientifically linked to those diseases.  The best routine is a quarantine tank and a stress free environment with good quality veggie foods, places to hide and a quiet area for the aquarium.  

   For more information see Fish diseases.

   Diseases that Surgeonfish and Tangs are susceptible to:  Marine Ich (white spot disease)Marine Velvet and Lateral Line Erosion (LLE)


   The Vlamingi Tang or Bignose Unicornfish is occasionally available at retailers and it is possible that it may be ordered. They are regularly available on the internet with juveniles starting around $55.00 and adults around $200.00 USD and up.


  • Fish Tales
    By Henry C. Schultz III
  • Unicorns:  More than a Myth in Reef Aquaiums
  • The Genus Naso
  • Reefkeeping Magazine™ Reef Central, LLC-Copyright © 2008 All rights reserved
    URL:  http://reefkeeping.com/issues/2005-07/hcs3/index.php
    Growth and longevity in acanthurid fishes; an analysis of otolith increments 
  • J. H. Choat*, L. M. Axe 
  • Department of Marine Biology, Jarnes Cook University, Townsville, Queensland 481 1, Australia 
  • URL:  http://www.int-res.com/articles/meps/134/m134p015.pdf
  • AQUARIUM FISH:  Fish Ethics and the Vlamingi Tang By Gregory Schiemer Copyright © 2002-2013 by Pomacanthus Publications, LLC, all rights reserved.
    URL:  http://www.advancedaquarist.com/2003/1/fish
  • AQUARIUM FISH:  Activated carbon affirmed as causative agent for HLLI disease
    By Leonard Ho
    Copyright © 2002-2013 by Pomacanthus Publications, LLC, all rights reserved.
    URL:  http://www.advancedaquarist.com/blog/activated-carbon-affirmed-as-causative-agent-for-hlle-disease
  • Hexamita:  Fish Hole in the Head Disease
    By Neale Monks, Ph.D.
    Copyright ©2013 I-5 Publishing, LLC. All rights reserved
    URL:  http://www.fishchannel.com/fish-health/freshwater-conditions/hexamita.aspx

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