The Acanthurus Achilles, commonly known as the Achilles Tang, is one of the most striking and challenging surgeonfish in the marine aquarium hobby. With its deep velvet-black body, vivid orange teardrop marking near the tail, and electric-blue fin edging, this species is a true showpiece reserved for advanced reef keepers who can meet its demanding requirements.
Natural Habitat and Aquarium Requirements
In the wild, the Achilles Tang inhabits surge zones and high-energy reef slopes across the Pacific, constantly grazing on filamentous algae in strong, turbulent water. Successfully keeping this species means recreating those conditions as closely as possible.
Tank Size and Aquascape
- Minimum tank size: 180 gallons (680 L) or larger for a single adult.
- Swimming space: Prioritize long, open areas for continuous swimming over cramped rock mazes.
- Rockwork: Provide stable structures with plenty of flow-through caves and ledges for grazing and shelter.
For more guidance on planning a system for active surgeonfish, see our article on tangs for large reef tanks.
Flow, Oxygenation, and Water Quality
- High flow: Use multiple powerheads or a gyre pump to create strong, random flow patterns that mimic surf zones.
- Excellent gas exchange: Surface agitation, a properly sized protein skimmer, and strong aeration are crucial.
- Stable parameters: Aim for 1.025–1.026 SG, 77–79°F (25–26°C), and very low nitrate and phosphate.
Pro tip: Achilles Tangs are extremely sensitive to swings in temperature, salinity, and pH. Use an auto top-off, reliable heaters, and regular testing to keep conditions steady.
Diet, Behavior, and Tankmates
The Achilles Tang is an obligate grazer that spends most of the day picking at algae. A well-fed fish is more resistant to disease and less likely to become aggressive.
Feeding the Achilles Tang
- Offer nori or dried seaweed on clips several times daily.
- Supplement with spirulina-based pellets and flakes.
- Rotate in frozen foods like mysis and enriched brine as treats, not staples.
- Encourage natural grazing by promoting healthy film and turf algae on rocks.
If you’re building a community of herbivores, our guide to the best herbivores for reef tanks can help you plan compatible species.
Temperament and Compatibility
- Semi-aggressive: Generally peaceful toward non-tang species but can be very territorial with other surgeonfish.
- Acanthurus-to-Acanthurus aggression: Avoid mixing with similar-shaped tangs (e.g., Powder Blue, Goldrim) in smaller systems.
- Best companions: Peaceful wrasses, anthias, clownfish, and dwarf angels that won’t outcompete it for algae.
Quarantine tip: Achilles Tangs are notorious for ich and other parasites. A dedicated quarantine tank with observation, proper nutrition, and, if needed, treatment is strongly recommended before adding to your display.
Is the Acanthurus Achilles Right for You?
The Achilles Tang is a breathtaking addition to a large, mature reef system, but it is not a beginner’s fish. It demands:
- Very large, stable, and well-established aquariums
- High, turbulent flow and top-tier filtration
- Frequent feedings of algae-rich foods
- Careful quarantine and disease management
If you’re still building experience, you might consider starting with a hardier species from our beginner saltwater fish list before attempting this high-maintenance showpiece. For aquarists prepared to meet its needs, however, the Acanthurus Achilles can become the centerpiece of a thriving, dynamic reef aquarium.
Sources
- Michael, S.W. (2001). Marine Fishes: 500+ Essential-To-Know Aquarium Species. Microcosm Ltd.
- Fenner, R. (2001). The Conscientious Marine Aquarist. TFH Publications.
- Rhyne, A.L. et al. (2009). “Trophic guild and bioerosion potential of aquarium fish.” Environmental Biology of Fishes.
By
