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Related FAQs: Achilles Tangs, Achilles Tangs 2, & FAQs on: Achilles Tangs Identification, Achilles Tangs Behavior, Achilles Tangs Compatibility, Achilles Tangs Selection, Achilles Tangs Systems, Achilles Tangs Feeding, Achilles Tangs Disease, Achilles Tangs Reproduction, AcanthurusAcanthurus Tangs 2Acanthurus Tangs 3, Surgeons In General, Tang ID, Selection, Tang Behavior, Compatibility, Systems, Feeding, Disease,

Related Articles Surgeonfishes/Tangs/Doctorfishes and Marine Aquariums, by Bob Fenner, species of Acanthurus: A. sohal, A. nigricans & A. japonicus

/The Conscientious Reef Aquarist

The Appropriately Named Achilles Tang, Acanthurus achilles


Bob Fenner

Surgeonfishes: Tangs for  Marine
Diversity, Selection & Care

New eBook on Amazon: Available here
New Print Book on Create Space: Available here

by Robert (Bob) Fenner

    A beauty for sure, with its velvety dark brown to black overall color offset with a blood-red oval patch distally on the flank, the Achilles Tang is real eye-candy. Unfortunately, as Surgeonfishes go in its genus, this is one of the more touchy species for aquarium care; being susceptible especially to capture and handling damage and its subsequent consequences. On a scale of susceptibility to the common protozoan diseases of marine fishes, Cryptocaryon and Amyloodinium it also ranks quite high... right up with its congeners, the Powder Blue (A. leucosternon) and Powder Brown (A. nigricans), frequently "importing" these scourges into newer marine aquarists systems who have yet developed the discipline of strict quarantine. Lastly in their ranking of disfavorable characteristics, the Achilles is subject to the twin vagaries of "poor adaptibility" and hence anomalous loss, and an often lack of interest in feeding... comparable to the Clown/Oriental/Pajama Tang of this genus, A. lineatus.

    But, as they say on late night television, "Don't change that channel" just yet... don't give up hope on the possibility of keeping the Achilles, though the probability is better in keeping other more suitable Acanthurus species, or members of the exemplary genera Zebrasoma and Ctenochaetus... There are ways, means of greatly improving ones odds in keeping this high-maintenance species... Including aspects of the environment, selection of better specimens, feeding and more.

Range, Natural Habitat:

Acanthurus. achilles Shaw 1803, Achilles tang. Widely distributed from Hawaii westward through Micronesia and Melanesia, an area called Oceania (also reported from Mexico's Baja tip). Though the best specimens do hail from U.S.s 50th State, success with this species can only be had by securing a healthy specimen, providing a large well-established living space, with high, consistent specific gravity and oxygen concentration. Shown below, a juvenile and adult Hawaii specimen and one in the Cooks 
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    Achilles tangs are encountered on shallow reef slopes in areas of high turbulence, usually feeding solitarily on algae, though may "pair up" as juveniles and occasionally are found in larger shoal associations.


    The picking out of specimens is a critical area with this species. MANY individuals are doomed... from incipient damage from collection, the vagaries of handling, transport... and outright stress. One very surprising quality of this species is its "soft-bodied-ness"... Once you've physically handled one, you'll agree that this fish is "soft" to the touch... much more so than other Acanthurids... this trait works to their disadvantage in being caught in the wild. Almost all Achilles are collected with the use of "fence nets"... lengths of two dimensional netting that are held up with small floats and down on the bottom with weighting... fishes are driven off a prospective collecting area, where they will return to in short order... and driven into these transparent walls... and subsequently hand-netted and placed via the hand nets into collecting buckets for holding and decompression... being pulled to the surface slowly. The process of hand-netting and transfer is a crucial time for Achilles... as they are often "pinched" in the net, and/or the hand of the collector in transfer... The other general means of collecting, especially larger (make that "too-large") specimens is to "pick them up" at night while they are lying down "sleeping" on the bottom. This is accomplished with hand netting and hands again... All this touching reeks havoc with this fish's slime coating, soft skin and body musculature... VERY often seen as discoloring to damage on their flanks... Sometimes you can even make out the fingers on one side, the thumb print on the other of a fish! This bit of observation is proffered to bring home the point that you want to:

1) Look for less to least damaged specimens... Ones with little to no markings on them.

2) Select a specimen of appropriate size... something twixt 3.5 to 5 inches overall length... Smaller specimens die easily and larger ones (usually caught at night) get beat too much and rarely adapt to captive conditions.

3) Don't buy it too early, nor too late. Recently arrived specimens should be left at your dealers for a few days to assure they will survive (most are lost the first day or two), and to assess how much damage it has encountered... Most markings will show in a day... and show improvement or worsening in a day or two following... Specimens that have been at shops that utilize copper prophylactically (MANY do) are often the cause of this and some other fish groups ultimate demise... though chronic poisoning and loss of needed intestinal microbial fauna. So... look for an Achilles that has been on hand for a few days, but no more than two weeks.

4) Some incidental damage is to be expected... and light bruising, some torn fin membranes are not a big deal, and will very likely heal in a matter of days to weeks. One debility though excludes purchase, and this is damage to the mouth. Such apparent rubbing almost always results in the loss of the specimen from not-feeding.

5) Look for the quality of "brightness"... that the specimen is out and about, picking at potential foods, AND is cognizant of its tankmates and your presence. Spaced-out individuals should be avoided.

6) To prophylactically dip/bath the specimen at the very least... If you can't be persuaded to quarantine it for a few weeks to allow it to rest up, adapt to captivity, and to grant you time to observe if it is hosting a hyper-infective state of Crypt and/or Velvet.


    See the notes above re where this fish is found... Achilles tangs require constant, high dissolved oxygen, an absence of nitrogenous et al. waste accumulation and good water movement.

    The ideal set-up for an Achilles is a largish volume (a minimum of  a hundred gallons plus), with plenty of well-established live rock, a good deal of pumping/circulation in at least two directions, and nooks and crannies to duck in and out of.

    And though this fish is found next to shore drop-offs in areas where there is variable salinity from run off from rain, Achilles tangs appreciate high and consistent specific gravity. Perhaps this harkens back to the issue of their having soft bodies... but do keep your water density near natural seawater strength (1.025-1.026).


    Though this species may sound "touchy", it is no push-over where holding its own with aggressive tankmates is concerned. Most all "regular" marines of about the same size will likely get along, and you'll find that the Achilles is "reef safe" to a very large extent, eschewing the sampling of all Cnidarian life.

    This is a one to a tank species, with two specimens rarely getting, growing to get along unless the system they're in is huge... hundreds of gallons. Periodic "sword play" with other acanthurids, related families like Rabbitfishes is to be expected, but if there is sufficient room, such psychological crowding can be tolerated.

    Other fish life and invertebrates that rely on micro-algae for food should be limited. Salarias, Atrosalarias et al. blennies, algae-eating snails and hermits for instance should be kept out or at minimal stocking densities. Other genera (Zebrasoma, a Paracanthurus, Naso...) of more generalized feeding tangs are semi-tolerated, once again, given adequate space for all.



    In the wild, Achilles spend all light hours scouring the rocky reef, apparently hopping about nipping at micro- and fleshy algae; mainly Greens and smaller Reds. This Acanthurus is among the least likely to take on a broader diet... thus offering sheet algae like Nori, some cultured material like "Ogo" (Red algae of the genus Gracilaria) and what can be cultured directly on copious amounts of live rock in your system is important. This all being stated, the excellent pelleted foods which are Pablo Tepoot's "Spectrum" deserve mention here. I have seen this species VERY readily take this commercial food... w/o previous exposure to it... And be sustained for years on nothing but. Yes... highly palatable and nutritious.

Disease/Health Issues:

    Many Tangs are labeled as "ich magnets" and the Achilles ranks high on this scale. Even with preventative dipping/bathing in pH-adjusted freshwater, and long quarantine, yours may well bring in protozoan complaints, or easily be amongst the first of your fish livestock to show such should an outbreak occur. 

    I encourage the use of a cleaner organism... my favorite choice here is the Lysmata amboinensis... which occurs over much the same range as the Achilles... Or one of the delightful Gobiosoma gobies... though their found elsewhere. The presence of the cleaner will go a long way to reduce stress in your system... even if strictly speaking these cleaner organisms can not, do not remove the parasites themselves.

    Due to its sensitivity to copper and lower specific gravity, I urge the use of dips/baths of short duration with formalin, moving afflicted specimens to new quarters, and quinine compounds for the common protozoan parasitic infestations.

    The condition HLLE (Head and Lateral Line Erosion) aka neuromast destruction, is common with this species when it is kept in non-reef settings. Systems that incorporate refugiums, macro-algae culture, lots of live rock, mud use... rarely bear witness to this mostly environmentally mediated erosive condition. Should yours show signs, the use of commercial food supplementing (HUFAs, Vitamins), generally reverses the effects.


    Like all Acanthuroids, this Surgeonfish has a protracted pelagic larval stage (floating about in the upper water column for weeks to months) and has not been produced via commercial aquaculture. One item of note however is the relatively frequent cross between it and the Powder Brown Surgeon, Acanthurus nigricans... a handsome hybrid for sure, and one that makes its way into pet-fish markets on a regular basis.


    Like its namesake, this Achilles has much going for it... Bold beauty, continuous swimming behavior, a live and let live attitude and one in which it can hold its own... What it lacks is toughness in its collection and subsequent handling, a need for large, well-established quarters, and care in picking out an initially healthy specimen, and quarantining/resting it and some medium attention in its feeding... Are you willing to provide these? If not, you're well-advised to look to other members of this genus, more suitable Acanthurids period.

Bibliography/Further Reading:

On Fishbase:

Stratton, Richard F. 1989. The achilles tang. TFH 1/89. 

Surgeonfishes: Tangs for  Marine
Diversity, Selection & Care

New eBook on Amazon: Available here
New Print Book on Create Space: Available here

by Robert (Bob) Fenner
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