Acanthurus bariene (Bariene Tang / Black-Spot Tang / Eye-Spot Surgeonfish)
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ✅ Yes
• Minimum tank size: 700L+ (preferably 1000L+ for adults)
• Adult size: ~50 cm (20 inches)
• Diet: Herbivorous (marine algae, seaweed, spirulina-based flakes/pellets, occasional meaty foods)
• Be aware of: Grows very large and needs a spacious tank with strong water flow. Can be territorial toward other tangs, especially if space is limited. Requires a high-fiber diet for digestive health.
Bariene Tang (Acanthurus bariene) – A Large and Majestic Reef Grazer
The Bariene Tang, also known as the Black-Spot Tang or Eye-Spot Surgeonfish, is a large, fast-swimming, and visually striking species from the Acanthuridae family. Native to the Indo-Pacific region, it is recognized for its unique dark body, bright yellow fins, and signature black spot near the tail. It is a powerful grazer, making it an excellent addition to large reef aquariums where it helps control algae.
Appearance and Coloration
The Bariene Tang is an impressive and unique-looking tang, featuring:
• A dark brown to olive-green body with a subtle maze-like pattern.
• A prominent black spot at the base of its tail, earning it the “Black-Spot Tang” nickname.
• Bright yellow dorsal and anal fins, which contrast beautifully against its darker body.
• A white crescent-shaped tail fin that adds to its elegant appearance.
Juveniles tend to have a lighter coloration, with a more pronounced pattern that fades slightly as they mature.
Natural Habitat and Behaviour
The Bariene Tang is found throughout the Indo-Pacific region, including areas around Australia, Indonesia, and the Philippines. In the wild, they prefer:
• Deep reef slopes and outer reef walls, where they graze on algae.
• Moderate to strong currents, simulating their natural reef environment.
• Patrolling large territories, which means they require significant swimming space in captivity.
In an aquarium, they are active swimmers, requiring open space for movement and live rock for grazing. They can be semi-aggressive, particularly towards other tangs of similar shape or diet.
Tank Requirements and Water Parameters
Due to their large adult size and need for open swimming space, Bariene Tangs require a spacious and well-maintained aquarium.
• Minimum tank size: 700L+ (1000L+ recommended for adults)
• Temperature: 23–26°C (73–79°F)
• pH: 8.1–8.4
• Salinity: 1.020–1.025
• Water movement: Moderate to strong, mimicking natural reef currents
• Filtration: High-capacity filtration and protein skimming are essential due to their high metabolism
A long tank (minimum 7-8 feet in length) is recommended to accommodate their swimming needs.
Diet and Feeding
Bariene Tangs are herbivores and constant grazers, requiring a high-fiber diet rich in marine algae to stay healthy.
Recommended foods include:
• Dried seaweed (Nori) – Essential for digestive health and immune support.
• Spirulina-based flakes and pellets – Provides necessary vitamins and coloration enhancement.
• Fresh macroalgae – Such as chaetomorpha or gracilaria.
• Occasional meaty foods – Enriched mysis shrimp or brine shrimp (as a supplement only).
Feeding multiple times per day is ideal, as they naturally graze continuously. A diet lacking algae can lead to nutritional deficiencies and stress-related illnesses.
Compatibility and Tank Mates
Bariene Tangs are semi-aggressive, especially toward other tangs or large herbivores. However, they are generally peaceful with non-tang species.
Best tank mates include:
✔ Large angelfish (Emperor Angelfish, French Angelfish)
✔ Wrasses (Harlequin Tusk, Bird Wrasse)
✔ Groupers and larger reef-safe fish
✔ Foxface Rabbitfish and large butterflyfish
Avoid housing with:
❌ Other Acanthurus tangs (e.g., Sohal Tang, Clown Tang, Powder Blue Tang) unless in a very large system.
❌ Other large herbivores that may challenge their dominance.
❌ Small, timid fish that may struggle to compete for food.
If mixing tangs, introduce them all simultaneously in a large system to reduce aggression.
Health and Disease Considerations
Bariene Tangs are hardy, but like all tangs, they can be prone to common saltwater fish diseases:
• Marine ich (Cryptocaryon irritans) – One of the most common issues; quarantine before introduction is recommended.
• Head and Lateral Line Erosion (HLLE) – Caused by poor diet, vitamin deficiencies, or suboptimal water quality.
• Nutritional deficiencies – If not provided with enough marine algae, they may become weak and lose colour vibrancy.
To maintain their health:
✔ Provide a varied, algae-rich diet with plenty of seaweed.
✔ Ensure stable water conditions to reduce stress.
✔ Quarantine new fish before adding them to the display tank.
Lifespan and Long-Term Care
With proper care, Bariene Tangs can live up to 15 years or more in captivity. Their hardiness, constant grazing behaviour, and striking appearance make them a valuable addition to large reef aquariums.
Why Choose a Bariene Tang?
✔ One of the larger tang species – Ideal for massive reef tanks.
✔ Excellent algae grazer – Helps control nuisance algae growth.
✔ Hardy and long-lived – Can thrive in well-maintained systems.
✔ Striking adult coloration – Develops blue highlights and a signature yellow mask.
⚠ Important Considerations Before Buying a Bariene Tang:
🚫 Not for small tanks – Requires a spacious aquarium with open swimming areas.
🚫 Can be semi-aggressive – Best kept as the only large tang unless in an extra-large system.
🚫 High-fiber diet required – Needs constant algae grazing to stay healthy.