Acanthurus lineatus (Clown Tang)
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ✅ Yes
• Minimum tank size: 600L+ (preferably 800L+)
• Adult size: ~38 cm
• Diet: Herbivorous (marine algae, seaweed, spirulina-based flakes/pellets, occasional meaty foods)
• Be aware of: Highly aggressive towards other tangs and similar-shaped fish. Requires a very large tank with strong water flow and ample swimming space. Prone to marine ich if stressed. Not recommended for beginner aquarists.
Clown Tang (Acanthurus lineatus) – A Striking and Highly Active Surgeonfish
The Clown Tang, also known as the Lined Surgeonfish, is a large and strikingly patterned species of tang from the Acanthuridae family. Native to the Indo-Pacific region, it is commonly found on coral reefs and coastal lagoons, where it grazes on algae-covered rock formations. With its bold horizontal stripes and energetic swimming style, the Clown Tang is an eye-catching but challenging species for marine aquarists.
Appearance and Identification
The Clown Tang has a vibrant, striped body with alternating blue and yellow-orange horizontal bands, giving it a distinct and unmistakable look. Its tail is typically bright yellow, and it features the characteristic scalpel-like spine near the base of the tail, used for defense. This species can grow quite large, reaching up to 38 cm (15 inches) in captivity, making it one of the larger tang species.
Natural Habitat and Behaviour
Clown Tangs are commonly found at depths ranging from 2 to 25 metres, preferring areas with strong currents and abundant algae growth. In the wild, they are known for their constant movement and can often be seen patrolling reef slopes in search of food.
In captivity, they require an exceptionally large tank with plenty of open swimming space. They are highly territorial and aggressive, especially towards other tangs or fish with a similar body shape. Due to their strong swimming instinct, they need strong water flow to mimic their natural reef environment.
Tank Requirements and Water Parameters
Clown Tangs are one of the most space-demanding species in the aquarium trade. They require a large, well-established marine system with excellent water quality.
• Minimum tank size: 600L+ (800L+ recommended for long-term care)
• Temperature: 23–26°C
• pH: 8.1–8.4
• Salinity: 1.020–1.025
• Water movement: Strong flow preferred
• Filtration: High-capacity filtration with a strong protein skimmer to handle bio-load
Since they are highly active swimmers, they do best in long tanks (minimum 6 feet in length) with plenty of space to establish their territory. Live rock with macroalgae growth will provide natural grazing opportunities.
Diet and Feeding
Clown Tangs are herbivorous grazers that require a diet rich in marine algae and vegetable matter. In the wild, they primarily feed on turf algae and filamentous algae, and their diet should be replicated in captivity as closely as possible.
Recommended foods include:
• Dried seaweed (Nori) – Essential for digestion and overall health
• Spirulina-based flakes and pellets – Helps maintain their vibrant colouration
• Fresh macroalgae – Such as chaetomorpha or gracilaria (if available)
• Occasional meaty foods – Enriched brine shrimp or mysis shrimp (as a supplement only)
They should be fed at least 2-3 times per day to support their high metabolism and constant activity. A diet lacking in algae can lead to nutritional deficiencies, including Head and Lateral Line Erosion (HLLE).
Compatibility and Tank Mates
Clown Tangs are notorious for their aggression, especially towards other tangs and similarly shaped fish. They can dominate a tank if not introduced carefully and should be one of the last fish added to a community setup.
Best tank mates include:
✔ Large angelfish
✔ Wrasses (fast-moving species)
✔ Large, semi-aggressive fish (e.g., Foxface Rabbitfish)
✔ Groupers and larger reef-safe fish
Avoid housing with:
❌ Other tangs (especially similar species like the Powder Blue Tang or Sohal Tang)
❌ Small, timid fish that may be bullied
❌ Slow-moving or delicate species that can’t compete for food
If keeping multiple tangs in a very large system, they should be introduced simultaneously to reduce territorial aggression.
Health and Disease Considerations
Clown Tangs are prone to marine ich (Cryptocaryon irritans) and other parasitic infections, particularly if they are stressed or introduced without quarantine. They should be quarantined before being added to the main tank to prevent disease outbreaks.
Common health concerns include:
• Marine ich (white spot disease) – Often triggered by stress or poor water quality
• Head and Lateral Line Erosion (HLLE) – Caused by poor diet, vitamin deficiencies, or low water quality
• Fin damage from aggression – Clown Tangs can fight with tank mates, leading to torn fins or injuries
Maintaining high water quality, strong filtration, and a balanced diet will help prevent these issues.
Lifespan and Long-Term Care
With proper care, Clown Tangs can live up to 10+ years in captivity. However, they are best suited for experienced marine aquarists due to their large space requirements, dietary needs, and aggressive temperament. If provided with a spacious, well-maintained environment, they can be a stunning and dynamic addition to a reef tank.