The Powder Blue Tang: An Iconic Beauty Demanding Exceptional Care

Powder Blue Tang (A. leucosternon)

Powder Blue Tang (A. leucosternon)

The powder blue tang (Acanthurus leucosternon) is a breathtakingly beautiful, widely recognized (even among non-hobbyists) marine fish that can be a real pain to maintain in aquaria. While it is possible to keep one successfully under ideal conditions, most specimens that enter the aquarium trade unfortunately perish within a short period after purchase.

Why such a dismal survival rate? Actually, this species has several points working against it as an aquarium candidate:

    • It’s highly susceptible to ectoparasites, such as marine ich (Cryptocaryon irritans).
    • It has to travel a really long distance from the point of collection in the Indian Ocean to the hobbyist’s tank (depending on where in the world he or she lives, of course), and it can get pretty beaten up and starved en route.
    • In nature, individuals claim a very large territory (much bigger than your average home aquarium), which can translate into hyper-aggressiveness toward any real or perceived resource competitor in aquaria.
    • It is more demanding with respect to water quality than many fish commonly available in the hobby.
    • Captive specimens don’t always learn to accept standard aquarium foods.

Despite these drawbacks, success with A. leucosternon is possible (though never guaranteed) under ideal circumstances as I’ve mentioned. So, how can you improve your odds of keeping a powder blue tang alive and thriving? Be sure to:

1) Provide a large, mature aquarium

I would consider a standard 125-gallon aquarium to be reasonable minimum housing for this species, but the bigger, the better. You want to ensure this fish has plenty of horizontal cruising space as well as ample live rock to nibble upon.

It’s also important to let the system mature for at least six months prior to introducing the specimen so parameters are stable and a steady crop of algae is available for grazing. A “sterile,” newly set-up system is not a good environment for A. leucosternon.

2) Choose a healthy specimen

Make sure any specimen you’re considering is robust-bodied, not thin and emaciated; appropriately active; uninjured and showing no obvious signs of disease; and demonstrably eating. If you have any doubts, pass the specimen by. Remember, the odds are stacked against success with this species, so any questionable behavior or symptoms in a prospective specimen should give you pause.

3) Quarantine the specimen for at least a month

This is always good advice, but given the powder blue tang’s disease susceptibility, skipping this step can be particularly reckless. Also, make sure the quarantine system is sufficiently large (I would recommend something at least in the vicinity of a 29-gallon tank for quarantining this species), has a mature biofilter, and offers the same exceptional degree of water quality it will (or should) enjoy in your display tank. Be prepared to do frequent water changes! I would also advise performing a freshwater dip as a hedge against ectoparasites before introducing the specimen to quarantine.

4) Maximize water movement

A. leucosternon demands robust circulation and a high level of dissolved oxygen, so be sure to provide ample turbulent water movement, not only throughout the water column, but also at the water surface to maximize gas exchange.

5) Minimize dissolved pollutants

Think: oversized protein skimmer and copious water changes. Also, the system should be minimally stocked and judiciously fed to keep the bioload to a minimum.

6) Avoid similar tankmates

A shoal of Powder Blue Tangs in the wild

A shoal of Powder Blue Tangs in the wild

    • Though powder blue tangs may form impressive shoals in the ocean, they won’t get along with conspecifics in the confines of your average home aquarium, so one to a tank is the rule. Also, avoid any other species that are similar looking/behaving and likely to be perceived as competitors for food or space, such as other tangs/surgeonfishes and rabbitfishes.

7) Go heavy on the greens

In addition to a good crop of algae growing in the aquarium, A. leucosternon should be offered a varied herbivorous menu, including items such as dried marine algae sheets, frozen herbivore formulations, algae-based flakes and pellets, and so forth. Several daily feedings are recommended.


If you enjoyed this post, subscribe to get our new posts in your email.
About Jeff Kurtz

Jeff Kurtz is the Co-founder/Editor of Saltwater Smarts, former Senior Consulting Editor for Tropical Fish Hobbyist Magazine, and the aquarist formerly known as “The Salt Creep.” He has been an aquarium hobbyist for over 30 years and is an avid scuba diver.


  1. Paul Baldassano says

    All tangs are schooling fish so if you have just one or two they will always be stressed as they never live alone in the sea. Stress in fish is the worst thing you could do to their immune system and it just doesn’t function well so the fish is very prone to all sorts of things from ich to sea gull attacks
    They never get over it. If you want to keep fifty powder blue tangs you would have more luck. Of course you would need a 50,000 gallon tank so you may have to sleep in your garage.

    • Jeff Kurtz says

      I don’t have any powder blue tangs but my wife still makes me sleep in the garage! What gives!?

  2. Is the powder tang similar in upkeep to the regal tang. I recently lost my regal tang and i bought him as an adult about 5 years ago. My Regal tang actually died after introducing another fish to the tank. Very frustrating because he was my favourite fish of all….after introducing the new fish which was a bi colour angel fish my tang got white spot…then recovered or so it seemed…then died a week later. Would also be interested to hear of any sea horse only tanks. I am looking to set one up with a new 180l tank soon

    • Jeff Kurtz says

      Hi Nick! There definitely are a lot of similarities between powder blue and regal tangs when it comes to factors like ectoparasite susceptibility; the need for a good-sized, mature tank with vigorous water movement; intolerance of dissolved organics; etc. Sorry to hear about your loss! I know how frustrating that can be!

      Thanks for the suggestion about covering seahorse tanks. Sounds like a really good topic for a future post. I’ve never kept seahorses myself, but what I do know about them is that you want to start with captive-bred specimens instead of wild-caught (they’re much more inclined to accept frozen foods rather than live only), they’re weak swimmers that require gentle water flow, they need structure in the tank that they can cling to with their prehensile tails (e.g., faux plants, corals, gorgonians), and they must be fed multiple times per day.

      if any other salties out there with experience keeping seahorses can add to/correct this info, please feel free to chime in!

  3. Paul Baldassano says

    I collected seahorses here in New York for decades (I still accidently collect them sometimes) they don’t really always live in places with little water movement, I get them in pretty fast moving channels. The best food for seahorses, and almost all fish is tiny, live saltwater fish. These are unavailable so many people try to “train” them to eat frozen Mysis. They will eat that but a seahorse is a creature with no stomach and were designed to eat continuously all day. They can live and even breed on a diet of live brine shrimp even though brine shrimp got a bad rap. Store bought brine shrimp are arguably a lousy food but if you raise the brine shrimp yourself (as I always did) they are much better nutritionally because they are eating and putting on pounds. OK, maybe not actually pounds, but you know what I mean. As the brine shrimp mature and start carrying eggs they become much more nutritious. I designed and patented a seahorse feeder (which I no longer sell)
    Here is an article about it I just found on the net.
    And here is a pair of horses I collected, the female is in the process of transferring eggs to the male, I took this in my reef tank. I raised the second batch of seahorses on brine shrimp alone that I grew to size by feeding yeast.

  4. Gus gutierrez says

    Setting 90gal tank, 5 Dec 2011 old with live rocks, about 9 corals, fish: large purple tang oldest resident in tank 2 yrs, large yellow tang, 1 1/2 yrs, large powder blue tang 15 mos old in tank, one large fox face one yr old. morning feeding three kinds of flakes, lunch feeding, one cube frozen bloodworms, one cube mysis and cube brine shrimp, every morning one square of Strang flat algae. 20gal RO water change every two weeks, oversized protein skimmer, large sump with bioballs and several layers of filter. Fish are healthy and thick bodied, no signs of stress, they get along well , no disease, no lateral disease on purple tang, blue powder tang as healthy as can be. Modesty aside I think my husbandry is okay or am I just lucky!

    • Jeff Kurtz says

      Hi Gus! I’d say you can probably credit a combination of your husbandry and good luck in choosing individuals that so far get along. Do keep a close eye on your specimens–especially the purple and powder blue tangs–to make sure they don’t pull a Jekyll and Hyde on you, turning from peaceful coexistence to combat.

      Another concern I have is that it sounds like you’re feeding a pretty heavy quantity of meaty foods. For your crew, I’d definitely skew the menu toward more algae-based foods and fewer meaty items, so you might want to shift in that direction gradually.

      Also, if my interpretation is correct that you’re feeding three frozen cubes (brine shrimp, mysids, and bloodworms) at every lunch feeding, that sounds excessive to me. Are you ending up with a lot of uneaten food in the tank or filter media?

      • Hi, I’m planning to have a powder blue tang in my 37,gallon tank, with in Stock is a maroon clown fish, blue tang and a yellow tang (Hawaiian), is that possible? My tank is running for about 7 months. Thanks for the reply.

Leave a Reply to Jeff Kurtz Cancel reply