Known as “Dory” in the Finding Nemo movie the Blue (Regal) Tang has moved to the 2nd most popular tang purchased for home aquaria!

Blue Regal Tangs are deep, yet compressed fish with an all over electric to deep blue coloring.  Their black markings resemble an artists paint palette, which they mix colors on and gains them the name Palette Tang.  They have a “V” shaped yellow tail fin that comes to a point in the caudal fin area and a black bar on the top and bottom edges..  The Indian Ocean specimens can have a yellow belly.   Some say males have a darker to black face and are more aggressive.  These tangs grow up to 12” (31 cm) or more and may live 30 to 45 years like most tangs.  Blue Regal Tangs are best kept by intermediate to advanced aquarists.

These tangs are probably the goofiest surgeonfish out there!   They have been known to just lay down on their sides to take a nap, although a newly introduced fish will do that if they are stressed too!  At times they will wedge themselves in between rock or coral so tight that it seems like they are stuck; however, they are fine and do not need to be rescued.  These tangs do not eat large amounts of algae like other tangs, in fact, they are planktivores, yet also considered omnivores and rarely eat algae.  They are the only tang in their genus, Paracanthurus, and are the second most sought after marine fish kept by hobbyists.

Blue Regal Tangs are moderately hardy if specific care is provided.  These very large tangs should be quarantined since they are very prone to parasites.  They are also more prone than other tangs to Lateral Line Disease and Hole in the Head disease due to poor water conditions and use of carbon.  Soaking their meaty foods in vitamin C can help them keep their bright coloring.  Just because they are large does not mean they can handle larger aggressive tank mates and tend to be the victim of attacks by these other fish.

Being most likely to be picked on by more aggressive tangs, the Blue Regal Tang does best alone, but will do okay with other tangs that are also relatively peaceful but only in tanks that are 400 gallons or more.  For example, they will do okay with the Yellow Tang, Naso Tang and various Bristletooth tangs like the Yellow-eyed Kole Tang since they all eat different foods and look very different.  In smaller tanks, they will become belligerent, however in appropriately sized tanks they are fine.  They will not bother any corals or inverts except for the ones they munch on in the reef.  Do not house with aggressive fish.

Provide a 6 foot minimum length tank that is at least 180 gallons by the time they are 8” long.  They can be kept in a 75 gallon until they are 5” long, a 125  until they are 8” long and should not be kept in a nano tank.  The temperature should be kept at 72 to 78˚F, pH 8.1 to 8.4 and the tank should have plenty of swimming space.  Since they are not reliant on algae, they do not need any special lighting if kept in a fish only tank yet will need to have their food supplemented with vitamin C in such a situation.

Dr. Jungle says….”Nemo’s best friend ‘Dory’ in the movie “Finding Nemo” certainly helped with the Blue Tang’s popularity!”

The Blue Tang is also known as the Regal Tang, Blue Surgeonfish, and Indo-Pacific Blue Tang. This gorgeous fish is readily available, easy to keep, and is very interesting to watch. We knew of one that would spend time everyday in play, chasing bubbles from the bottom of the aquarium to the top!

Scientific Classification

Species: hepatus

Blue Tang – Quick Aquarium Care

Aquarist Experience Level:Intermediate
Aquarium Hardiness:Moderately hardy
Minimum Tank Size:180 gal (681 L)
Size of fish – inches:12.0 inches (30.48 cm)
Temperature:72.0 to 78.0° F (22.2 to 25.6&deg C)
Range ph:8.1-8.4
Diet Type: Omnivore
blue regal tang fish feeding with other fish
Image Credit: David Clode, Unsplash

Habitat: Distribution / Background

The Blue Regal Tang, Paracanthurus hepatus, was first described by Linnaeus, in 1766.  The genus Paracanthurus is Greek for “the side of” (para), “thorn” (akantha) and “tail” (oura), and was once put in the Acanthurus genus.  Their common names are descriptive of their pattern, color and location and these are:   Blue Surgeonfish, Blue Tang, Dory Fish, Flagtail Surgeonfish, Hepatus Tang, Hippo Tang, Indo-Pacific Bluetang, Palette Surgeon, Palette Surgeonfish, Surgeonfish, and Wedge-Tailed Blue Tang.  Okay, so “Dory Fish” is not a common name, however, I have heard adults use it, so I threw it in there!

They are located in the Indo-Pacific from East Africa, the Mascarene Islands, to Kiribati, then north to southern Japan and then southward towards the southern part of the Great barrier Reef, New Caledonia, and Samoa.  They like clear, swift water found in seaward reefs from depths of 3 to 134 feet (10 to 40 m) feeding mostly on zooplankton and other inverts and occasionally on algae.  Adults are found in loose groups 3 to 6 feet (1 to 2 m) above the bottom.  Juveniles and subadults are found in groups near isolated groupings of the Cauliflower Coral (Pocillopora eydouxi) which is an SPS coral, and will hide themselves snuggly within the coral branches when frightened.

The Blue Regal Tang is on the IUCN Red List for least concerned since they inhabit protected areas and have a stable population trend.

  • Scientific Name: Paracanthurus hepatus
  • Social Grouping: Groups
  • IUCN Red List: LC – Least Concern


Blue Regal Tangs are flat, yet deep fish that are longer in the body, more like Naso Tangs than the other genus of tangs.  They have an over all electric to deep blue coloring with black markings that resemble an artists paint palette that they mix colors on.  Pale blue may indicate illness.  Their yellow tail fin comes to a point into the caudal fin area, creating a yellow “V” shape trimmed in a black bar on the top and bottom edges.  In the Indian Ocean, some specimens have a  yellow belly, with some speculating these are males.  It is possible, like the closely related Acantherus, that females are larger.  Juveniles have a less developed black “palette” outline that eventually forms a “hole” right behind the head area when they are adults.  These tangs grow up to 12” (31 cm) or more, reaching 80% of their length by 4 to 5 years old, or 9.6” in length.  Before that time, they should be in their 180 gallon tank.  Like other tangs, they probably live 30 to 45 years (Choat & Axe, 1996)

  • Size of fish – inches: 12.0 inches (30.48 cm)
  • Lifespan: 45 years – 30 to 45 years (Choat & Axe, 1996)

Fish Keeping Difficulty

Blue Regal Tangs are one of the harder tangs to care for, however an aquarist can have success if basic needs are cared for.  They are not quite as delicate as the Achilles Tang, but it is still challenging.  Many times they are too frightened to come out and eat, thus withering away.  Aggressive tank mates will keep them hidden.  Tank size is another one of the more important variables, along with providing adequate filtration, skimming and room for them to swim comfortably.  Give them lots of little holes and arches to swim in and out of and provide large enough crevices to match up with their size as they grow to sleep in.  Juveniles need quite a bit of hiding areas since they are very skittish.  Choose a fish that is active and will eat when fed and has bright coloring and no signs of illness.  They are very prone to crypt, bacterial infections from poor water quality, color loss, Lateral Line Disease and Hole in the Head Disease more so than other tangs.  (See Foods and Diseases)  Having them in a reef is best since the copepods and other organisms that eat algae will provide them with the vitamins they need.

Be very careful of their caudal fin spine, as it is venomous and will cause redness and swelling along with pain for some people.  Disinfect the inflicted area and watch for infection.  Capture the tang in a container, not a net since it may snag the spine and tear it, causing an infection of the caudal fin area.

  • Aquarium Hardiness: Moderately hardy
  • Aquarist Experience Level: Intermediate

Foods and Feeding

Blue Regal Tangs are planktivores or for the sake of simplicity, omnivores since they occasionally eat algae.  They eat zooplankton in the wild that have fed on phytoplankton and algae, so they get any vitamins they need through that type of feeding.  Most will accept marine algae, and since that is the most nutritious, it should be the only veggie offered, however this should not be their main diet.  This tang will enjoy eating meaty foods like finely Chopped fresh or frozen shrimp, vitamin-enriched brine shrimp, mysis shrimp and gut filled (by algae) live brine and mysis shrimp.  

To help with Lateral Line Disease and Hold in the Head Disease, avoid using activated carbon and enrich any freeze dried meaty foods, flake or pellets with vitamin C.

  • Diet Type: Omnivore – More zooplankton and meaty foods.
  • Flake Food: Yes
  • Tablet / Pellet: Yes – Soak with vitamin C
  • Live foods (fishes, shrimps, worms): Some of Diet – Gut loaded with quality marine algae.
  • Vegetable Food: Some of Diet – Only marine algae, and not main food.
  • Meaty Food: Most of Diet – They are planktivores that occasionally eat algae.
  • Feeding Frequency: Several feedings per day
blue regal tang fish
Image Credit: David Clode, Unsplash

Aquarium Care

A large and quick agile swimmer it will spend a good deal of its time in the open water and moving in and out of crevices. 

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 10% bi-weekly to 20% monthly, depending on bioload.

Fish only tanks:*
-Medium sized up to 90 gallons, perform 20% to 30% monthly depending on bioload. 
-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.

  • Water Changes: Bi-weekly

Aquarium Setup

Although tiny babies can be seen in nano tanks, this is a very short lived and unacceptable environment since they will reach 9.6” by the time they are 4 or 5 years old.  Until then, between 2 and 5” they can be kept in a 75 gallon tank, from 5 to 8” a 125 gallon tank, then a 180 gallon tank by the time they are 8” long.  Provide a matured tank with stable conditions with lots of live rock for juveniles to hide and as they grow, and large enough crevices for them to sleep in at night.  Temperatures should be between 72 – 78˚F with a pH of 8.1 to 8.4 and normal ocean salinity.  All these parameters need to be stable and a strong water flow that provides water surface breakage along with a good skimmer is needed to keep water quality high and oxygen levels suitable.  They need open spaces to swim and are not as dependent on huge amounts of rock for algae as they are for hiding.  

  • Minimum Tank Size: 180 gal (681 L) – 75 gallons up to 5″ 125 gallons up to 8″
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Plus Hiding Places – Juveniles are very skittish.
  • Substrate Type: Any
  • Lighting Needs: Any
  • Temperature: 72.0 to 78.0° F (22.2 to 25.6&deg C)
  • Breeding Temperature: – unknown
  • Specific gravity: 1.023-1.025 SG
  • Range ph: 8.1-8.4
  • Brackish: No
  • Water Movement: Strong
  • Water Region: All

Social Behaviors

Blue Regal Tangs are semi-aggressive, yet peaceful towards non-tangs.  They are one of the more peaceful tangs, often becoming victims to more aggressive tangs or other aggressive tank mates.  As juveniles, they will tolerate each other, but they should be housed singly as adults and will not tolerate their own kind or even some Acanthurus of similar color.

If you wish to house them with other tangs, choose those who eat different foods, look different and are from different genus.  One example of mixing tangs, would be a Blue Regal Tang, Naso Tang (also more of a planktivore/herbivore), Yellow-eyed Kole Tang (detritus eater), and a Purple or Yellow Tang (herbivore).  These tangs are from different genus’ and this can be done in a tank that is 400 gallons or more (due to the size of those other tangs listed).  Adding them together as juveniles is best (again adding the bristletooth first), rather than adding a new one later when territories have been established.  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 with other tangs.  Adding a tang to a tank that already has tangs that have staked out there territory can cause problems, however, rearranging rock work can help alleviate the stress.  There will be aggression towards the new tang, so keep an eye on their behavior and remove them if they are constantly hiding or up in the corner of the tank.  Avoid triggers, puffers, and other aggressive fish which can stress your tangs out.  If your tang is “posturing” and using his scalpel to whack a tank mate, then remove that tank mate or the tang. 

The Blue Regal Tang will not graze on algae very often, but on the up side, they are completely disinterested in corals since they are planktivores!  This makes them a striking addition to a large reef tank!  Still, glue town corals since they like to dart around, typical for a tang.

Inverts are safe, however they will eat any zooplankton, copepods and amphipods that are hiding in algae.  They will not decimate the population, however, but these creatures should be present and thriving before adding your tang.

  • Venomous: Yes – Caudal spine is venomous.
  • Temperament: Semi-aggressive – Peaceful towards non-tangs.
  • Compatible with:
    • Same species – conspecifics: Sometimes – Juveniles only.
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Safe
    • Monitor – Large dottybacks and aggressive damsels should not be housed with juvenile Blue Regal Tangs.
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor – Only keep with more peaceful tangs of different genus and diet.
    • Large Aggressive, Predatory (lionfish, groupers, soapfish): Monitor – Only house when tang is much larger.
    • Monitor – They will not bother mandarins and seahorses and pipefish should have their own tank.
    • Anemones: Safe
    • Mushroom Anemones – Corallimorphs: Safe
    • LPS corals: Safe
    • 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: Safe
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Safe
    • Copepods, Amphipods, Mini Brittle Stars: Safe

Sexual differences

  Unknown, but it is possible, like their close relatives the Acanthurus genus that females may be larger.  Some say the ones with the darker or black face are males or if they have a yellow belly.  Males are said to be more aggressive.

blue tang fish
Image Credit: neelsky, Shutterstock

Breeding / Reproduction

Since the Blue Regal Tang is most closely related to the Acanthurus genus of tangs, it is possible they have similar reproduction practices.  Unlike other genus of the tang/surgeon family, the females of the genus Acanthurus are larger than males.  They are open water spawners and form pairs.  These pairs seem to stay together even within groups.  The male may exhibit color changes during spawning to attract female and to warn rival males.  If they are in a large school, a pair will break away and rise upward toward the surface and release their gametes. These little floating fertilized eggs are spherical and have a single oil globule to aid in their buoyancy and dispersal.  Each egg measures around 0.17 mm in diameter.   Once they hatch, the larvae look like little kites with a long snout with a small mouth, and they stay in this state for 42 to 68 days.  During this time, they fall prey to fish and other marine animals.  Once they reach around 1 inch, give or take (23 to 33 mm), the  larvae are then changed into the juvenile stage.  Once they are ready to join the reef, the larvae settle out of the water column and develop into these 1” juveniles, seeking the protection and food sources of the reef and seagrass habitats. 

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

  • 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 microfauna 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.

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.  

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


The Blue Regal Tang is often available online and can start for as little as $30.00 USD (Jan 2015) for a tiny 1 to 2” baby.

Popular Searches


  • Animal-World References – Marine and Reef
    By Scott W. Michael
    T.F.H. Publications – Copyright © 2001 by T.F.H. Publications, Inc.

Featured Image Credit: Podolnaya Elena, Shutterstock