With whimsical colorful stripes, their unique markings give them the name Clown Tang, Lined Tang, or Blue-lined Surgeonfish!

   Clown Tangs are blue with yellow and black-edged blue stripes that run horizontally on the body, head and face.  Their belly is grayish white, with their fins having fainter yellow and blue stripes that make them appear green from a distance, although they have pale pectoral fins.  The tail fin is deeply crescent or moon shaped and males have long streamers.  There is some variation on the stripes and fin coloring depending on location.  Females are larger than males, in the Acanthurus genus.  This tang has been reported to grow up to 15” (39 cm), and since tangs grow to 80% of their total length within the first 4 to 5 years, they will reach 12″ by then if they are females.  Tangs have a life span of 30 to 45 years (Choat and Axe 1996).  The Clown Tang is suited for advanced to expert aquarists.

   The Clown Tang is one of the most aggressive species in the Acanthurus genus.  They have a larger than average caudal spine and they are happy to use it, whether it is another fish or the aquarists hand.  Their beauty sets them apart from the other tangs and their appearance is unique to them, with only the Sohal Tang having a slightly similar look.  The yellow on the Sohal Tang is found in a couple of places, but mainly their pectoral fin has the coloring.  This yellow can be orange or pale when stressed and their stripes are black and blue to gray and tan.   The Clown Tang will go after other fish with similar shape and taste buds for their preferred foods.  They have been known to chomp a crustacean here and there.  Their caudal spine is venomous and can cause painful wounds.  These fish school to spawn in large aggregations, however, they still spawn in pairs.

   These fish are difficult to care for, for various reasons; however, if all their needs are met and a healthy specimen is acquired, they can do quite well.  First and foremost, a very large tank is needed, which cannot be over emphasized!  The tank should be mature, with plenty of algae growing, such as large filamentous and small fleshy macro algae.  Whether it is a reef or fish only,  sufficient lighting is needed to support their food.  This fish should be purchased around 4- 5″ or larger since smaller specimens are difficult to maintain.  Do not buy your juvenile with the thoughts of “upgrading” to a large tank later, since they grow very fast.  The next challenge is the need for highly oxygenated water that is very clean.  This is a challenge due to their large appetites and massive “output” typical of tangs.  The third challenge is that they are just mean, mean, mean and this limits the aquarists options as far as other tank mates.  On top of that, Clown Tangs are not super hardy, have a dismal survival rate, and suffer during shipping.

   These fish are aggressive in the wild and will kick the other fish’s butts in captivity.  Clown Tangs are VERY territorial with a male defending a very large territory that have several females.  This really cannot be duplicated in the home aquarium since picking out males and females as juveniles is near impossible.  Do not house with anything but large aggressive fish and avoid fish that are peaceful, have similar feeding habits and similar body shape.  Avoid housing with other tangs.  While they may be fine as juveniles they will become very mean as adults.  They have been known to eat crustaceans and large polyp stonies even if well fed.

   Minimum and we mean MINIMUM tank size is 250 gallons (946 liters) that is mature with lots of algae growth.  Plenty of rock work that provides growing surface for algae is recommended, however the top of the tank should have open swimming space due to their constant swimming habits.  Water movement should be strong, well oxygenated and clean.  They swim at all levels, swim non-stop and do better in temperatures that are a little lower since there will be more oxygen.  Their temperature range should range between 72-78° F (22-26°C).  Ph should 8.1 to 8.4.

For more Information on keeping marine fish see:
Guide to a Happy, Healthy Marine Aquarium

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Acanthuridae
  • Genus: Acanthurus
  • Species: lineatus
Clown Tang – Quick Aquarium Care
  • Aquarist Experience Level: Advanced
  • Aquarium Hardiness: Difficult
  • Minimum Tank Size: 250 gal (946 L)
  • Size of fish – inches: 15.0 inches (38.10 cm)
  • Temperament: Aggressive
  • Temperature: 72.0 to 78.0° F (22.2 to 25.6&deg C)
  • Range ph: 8.1-8.4
  • Diet Type: Herbivore
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Habitat: Distribution / Background

   The Clown Tang, Acanthurus lineatus, was first described by Linnaeus, in 1758.  They have quite a few common names, all of which describe their physical appearance.  These are:  Clown Tang, Blue Banded Surgeonfish, Bluelined Surgeonfish, Clown Surgeonfish, Clown Surgeon, Lined Surgeon, and Striped Surgeonfish.  The names, Clown Tang and Lined Surgeonfish, are probably the most common.  Acanthurus is Greek for “thorn tail,” and lineatus is the species loosely named after Mr. Linneaus.

   The Clown Tang is found in the Indo-Pacific, from East Africa to the Hawaiian, Marquesas and Tuamoto Islands then northward to the southern part of Japan and south to the Great Barrier Reef and New Caledonia.  They are replaced by the Sohal Tang (Acanthurus sohal) in the Red Sea.  These tangs are found in the surge zones of exposed seaward reefs and will form schools to spawn and can be found from 3 to 10 feet (1 to 3 meters) mainly feeding on benthic weeds and algae of various genus including Caulerpa, Cladophora, Codium, Dictyota, Jania, Laurencia, Padina, Polysiphonia, Sphacelaria, and Turbinaria; although, other algae may be eaten.  They have been observed eating small crustaceans and large polyp stony corals in captivity, although they are generally herbivores.

   Juveniles are solitary.  Adult males usually are solitary and have a large territory with several females; however, the Clown Tang will come together in large groups to spawn.

   They are on the IUCN Red List for Least Concern, with a stable population trend.  The Clown Tang does inhabit protected areas, which keeps their population size acceptable; although, some heavily fished areas have seen a decline in numbers. 

Similar Species:

  • Sohal Tang (Acanthurus Sohal):  This fish referred to as the Red Sea Clown Tang yet has darker striping alternating with pale coloring and darkly edged fins.  Their pectoral fins have yellow and they have an orange horizontal “dash” over their caudal spine.  They are slightly larger than the Clown Tang
  • Scientific Name: Acanthurus lineatus
  • Social Grouping: Varies – Solitary as juveniles, harems as adults, schools as well
  • IUCN Red List: LC – Least Concern – The Clown Tang is on the IUCN Red List for Least Concerned.


   The Clown Tang has a deep oval shaped body, with minute scales and a deep crescent shaped tail fin, as an adult.  Their horizontal stripes are bright yellow, which are contrasted by blue stripes that are outlines in a thin dark blue to black edging.  The fins have the yellow and blue striping; however, the color is more subtle, which gives the fins a greenish hue.  The pectoral fins are clearish and their belly is a pale grayish white to grayish blue.  Their caudal fin area houses larger than average scalpels; which are venomous.  Juveniles are similar to adults. 

   Females of the Acanthurus genus are larger than males, with females reaching 15″ (38 cm) and males are closer to 9.8″ (25 cm).  Tangs grow 80% of their total length within the first 4 to 5 years of life, reaching 12″ by then if females.  Tangs in general, if healthy can live 30 to 45 years (Choat and Axe 1996), although they probably will live less in captivity.

Picture of a Clown Tang, Lined Tang, or Blue-lined Surgeonfish - Acanthurus lineatus

  • Size of fish – inches: 15.0 inches (38.10 cm) – Females are larger. Males reach 9.8″ as adults, both only reach 80% of these lengths by 4 or 5 years, then growth is slower. Choose a fat, active and eating Clown Tang that is at least 4″ long.
  • Lifespan: 30 years – up to 45 years (Choat and Axe 1996), possibly less in captivity.

Fish Keeping Difficulty

   Clown Tangs are difficult to care for, however if all the “rules” are followed you may have success!  First, do not buy small babies under 4″ or fish that are thin, ragged, not eating or have any visible sores.   Sadly, Clown Tangs do not ship well. Any Clown Tang that is NOT in constant motion should be left behind.  The tank needs to be a minimum of 250 gallons (946 liters), and this tank should be the one the juvenile is introduced into.  They also need the tank to be mature, producing lots of edible algae, which will help in their adjusting to captivity.  Feed them 3 times a day with good quality macro algae, flake and pellet and provide Nori or other algae sheets between meals.  The Clown tang can be 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 and avoid activated carbon. 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 since they produce copious amounts of waste.  All surgeonfish need an aquarium with plenty of aeration, a strong current will help to provide good oxygenation.

   Clown Tangs will do best in a mature environment that provides consistency in water temperatures of 72 – 78˚F and 8.1 to 8.4 pH.  Lower temperatures have higher levels of dissolved oxygen which is suggested for these high energy tangs.  Naturally growing algae needs to be supported by proper lighting.  They are found swimming on all levels of the tank and wedge themselves in between rocks and crevices at night.

  • Aquarium Hardiness: Difficult – Challenges are tank size, very clean water, feeding needs, and tank mates.
  • Aquarist Experience Level: Advanced

Foods and Feeding

   The Clown Tangs are herbivores according to fishbase.org where all stomach contents revealed only filamentous and fleshy algae.  It is not too picky about foods once it gets settled, and like most surgeonfish this can be accomplished by initially offering a good macro algae.  Since the Clown Tang is so delicate, avoiding meaty foods may be the best choice, since the copepods and amphipods in the algae they eat may be all they need.  Feed your herbivores first if housed with carnivores or omnivores.  Provide prepared frozen marine formulas, flake and tablets containing marine algae or Spirulina.  Japanese Nori or other seaweed can also be offered in between meals.   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.  Growing algae in a separate tank is a good practice.

   Providing a vitamin supplement (including vitamin C) can help provide for the nutritional needs of surgeonfish, 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 for their surgeonfish, such as previously boiled or frozen zucchini, broccoli, spinach, and leaf lettuce.  Natural algae has denser calories and nutrition for tangs, so keep the human food to a minimum for lasting success.

  • Diet Type: Herbivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes
  • Vegetable Food: All of Diet – Natural marine algae is more nutritious than human veggies.
  • Feeding Frequency: Several feedings per day – At least 3 times a day as adults, more as juveniles.

Aquarium Care

Reef tanks:
-Medium sized up to 90 gallons, perform 15% bi-weekly. 
-Large Tanks 100 gallons and over, once water is aged and stable can be changed 15% bi-weekly to 30% monthly, depending on bio load.

Fish only tanks:*
-Large Tanks 100 gallons and over, once water is aged and stable can be changed 30% every 4 weeks depending on bio load.

   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. 

  • Water Changes: Bi-weekly – 15%

Aquarium Setup

   Being very large and active swimmers, your Clown Tang will need lots of open areas, in a minimum tank size of 250 gallons.  Tank should be at least 6 feet in length and it should be mature enough to have lots of naturally growing algae.  Small juveniles should be housed in this large tank from the beginning.  The exception could be keeping them in a 75 gallon until they are 5,” since there is a 250 gallon tank maturing and ready for the juvenile when they are ready to transfer.  To feel secure they also need rocks/ corals with many nooks and crannies to hide in and to wedge themselves into at night for sleeping. This fish will not bother most corals however they have been known to munch on Large Polyp Stonies, but it can still can be kept in a reef.  As for inverts, in captivity they have been seen eating small crustaceans; however, I would speculate that maybe they ate them because they were eating their food due to their aggressive nature and the fact that in the wild, their stomachs never had any trace of crustacean flesh.   It is doubtful this is a food requirement but be aware of this observation if you have small critters like sexy shrimp for example.  Since Clown Tangs will graze on a wide variety of algae, it is highly useful in a reef environment.  Keep corals glued down, as their quick speeds may topple them. They thrive well in tanks with algae growth, so if housing in a fish only tank, provide lighting to help algae grow for them.  The temperature they prefer is 72 to 78˚F (22 to 26˚C), normal ocean salinity, and a pH that is 8.1 to 8.4.  All of these parameters should be stable and should not fluctuate.   Provide an area of strong linear water flow for them to swim against and be sure the water quality stays high.  Tangs produce a lot of waste, so the larger the tank, the easier it is to keep clean since they are sensitive to organic waste.  A strong skimmer and good filtration is recommended for long term health.  They are found on all levels of the tank and hide in rock work at night.

  • Minimum Tank Size: 250 gal (946 L)
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Amount – Provide open areas for this active swimmer.
  • Substrate Type: Any
  • Lighting Needs: Moderate – normal lighting – Enough to provide good algae growth.
  • Temperature: 72.0 to 78.0° F (22.2 to 25.6&deg C)
  • Specific gravity: 1.023-1.025 SG
  • Range ph: 8.1-8.4
  • Brackish: No
  • Water Movement: Strong – Well filtered and oxygenated.
  • Water Region: All – They hide at night wedged between rocks in a crevice or cave.

Social Behaviors

   Clown Tangs are aggressive and just don’t play well with others.  On top of that, their caudal spine is larger than average and venomous.  Besides that, they are not reserved about using it!  Unless you have a tank that is thousands of gallons, do not house with other Clown Tangs.  They have no sexual differences as juveniles, and sex can only be determined once they are older and their size will reveal this necessary fact.  For that matter, they are so aggressive that they will attack other tangs, especially those with a similar shape or those who eat the same foods.  Even in a 250 gallon tank, aquarists note that they will still attack other fish that they deem a threat in their “territory,” which essentially is the entire tank!  Don’t fool yourself that when they are juveniles and not attacking other tangs and fish that they will not change as they grow!  Some have had their Clown Tang baby attack larger tangs!  Some have had success with adding the Clown Tank with a larger Sailfin Tang as juveniles in a 250 gallon tang.  Monitor their progress as they age.

   When it comes to other fish, they will attack non tangs who have a similar shape or eat the same foods.  They will attack peaceful fish and they have been known to attack aquarists!  For example, this would mean that Lawnmower Blennies are off the list for those 2 reasons mentioned above.  House with aggressive fish that an hold their own, like large groupers (not large enough to swallow a juvenile Clown Tang), semi-aggressive triggers, large eels, and fast moving large wrasses (remember to feed your carnivores second).  It may be wise to avoid Lionfish due to the Clown Tangs propensity to start fights and this tang’s large size make it an easy target for a Lionfish.  Puffers may be picked at, so monitor them.

   They are great in reefs since they eat so much algae to the benefit of the corals.  Clown Tangs have been observed nipping at Large Polyp Stonies even when well fed; however, other corals should be fine.  Experiment by adding the coral and seeing how the tang responds.

   Clown Tangs will not bother inverts, though some have seen them eat small crustaceans.  This makes me wonder, since they are herbivores, if these little crustaceans were eating their crop of algae or if they were just among the crop when eaten and just not spit out later.

  • Venomous: Yes – have been known to inflict painful wounds with their larger than average caudal spine.
  • Temperament: Aggressive
  • Compatible with:
    • Same species – conspecifics: Sometimes – In tanks that are thousands of gallons and only one male and several females.
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Threat
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Threat
    • Monitor – Larger dottybacks and those damselfish that eat different foods may be okay.
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor – Avoid other tangs and angelfish with the same food preferences.
    • Large Aggressive, Predatory (lionfish, groupers, soapfish): Monitor – As long as the predatory fish is not large enough to swallow a juvenile. Avoid Lionfish.
    • Threat
    • Anemones: Safe
    • Mushroom Anemones – Corallimorphs: Safe
    • LPS corals: Monitor – Even Clown Tangs that are well fed have been observed nipping at LPS in captivity.
    • SPS corals: Safe
    • Gorgonians, Sea Fans: Safe
    • Leather Corals: Safe
    • Soft Corals (xenias, tree corals): Safe
    • Star Polyps, Organ Pipe Coral: Safe
    • Zoanthids – Button Polyps, Sea Mats: Safe
    • Sponges, Tunicates: Safe
    • Shrimps, Crabs, Snails: Monitor – Small specimens may be accidentally or purposely eaten occasionally.
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Safe
    • Copepods, Amphipods, Mini Brittle Stars: Safe

Sex: Sexual differences

  Although males and females are the same color and have the same markings, females are larger by about 5″ as adults, which is typical in the Acanthurus genus.  Females reach 15″ as adults and males reach 9.8″ as adults, however they reach 80% of their adult size in the first 4 to 5 years then grow at a much slower rate.

Breeding / Reproduction

   In the evening, just before or after the full moon, the Clown Tang will form a group and spawn in the open water as pairs, scattering fertilized eggs.  Similar to other Acanthurus, each egg has a single oil droplet to keep it floating, or pelagic.  In 24 hours, give or take, they hatch into little clear larvae called “acronurus”. These have large pectoral fins and large eyes with a body that is diamond shaped and flat with a triangular head. Only when the acronurus reaches 2-6 mm, will the scales, anal fins and dorsal fins begin to develop.  As they mature, they will drift inshore and change into juveniles. This metamorphosis occurs within about a week. Around 9 months of age they are sexually mature.  Females are slightly larger when sexually mature. 

   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. 

    Probably will not be accomplished in captivity. See the description in the Breeding Marine Fish page.

  • Ease of Breeding: Unknown

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, Lateral Line Disease, and parasitic infections such as protozoa (including Cryptocaryon), worms, etc.     

   For Crypt, 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 spp.) or cleaner shrimp can help them by providing this cleaning service in the home aquarium.  As for treatment, some tangs are sensitive to copper because they have an important micro fauna in their digestive system, so prolonged or continuous use of a copper treatment is not advisable.  It is also said that pellets soaked in garlic may help fend off Marine Ich.

   Providing a vitamin supplement (including vitamin C) can help provide for their nutritional needs, and vitamin C can help reduce Lateral Line Erosion (LLE) which may be caused by activated carbon. Enriching foods can be done by soaking dried pellets with liquid vitamins, adding vitamins to the food, or adding a liquid vitamin into the water.  Some hobbyists also report success with supplemental foods such as previously boiled or frozen zucchini, broccoli, spinach, and leaf lettuce; however, marine algae are best. 

   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.   


   Clown Tangs are seasonal and available at a much lower price than their cousin the Sohal Tang.  Plan to only pay about $50.00 to $60.00 (USD 2014), for a small baby.


Animal-World References: Marine and Reef

URL: http://www.liveaquaria.com/product/prod_display.cfm?c=15+43+340&pcatid=340

AQUARIUM FISH:  Surgeonfishes, A.K.A. the Tangs
By James W. Fatherree, M.Sc.
Copyright © 2002-2013 by Pomacanthus Publications, LLC, all rights reserved.
URL:  http://www.advancedaquarist.com/2009/12/fish