Zebrasoma rostratum (Black Tang)
• Small fish safe: ✅ Yes
• Small invert safe: ✅ Yes
• Coral safe: ✅ Yes
• Minimum tank size: 500L+ (Preferably 700L+ for long-term care)
• Adult size: ~22–25 cm
• Diet: Herbivorous (marine algae, seaweed, spirulina-based flakes/pellets, occasional meaty foods)
• Be aware of: Rare and expensive species. Can be territorial toward other Zebrasoma tangs. Requires a high-fiber diet to maintain health. Prone to marine ich if stressed.
Black Tang (Zebrasoma rostratum) – A Rare and Stunning Deep-Water Surgeonfish
The Black Tang is one of the most rare and sought-after tang species in the marine aquarium trade. With its deep black coloration, elongated snout, and graceful swimming motion, it is considered a showpiece fish for advanced aquarists. This species is native to the deep reefs of the Pacific Ocean, making it more difficult to collect and contributing to its high price and rarity. Despite its exclusive status, the Black Tang is a hardy and algae-grazing species that thrives in large, well-maintained reef tanks.
Appearance and Coloration
True to its name, the Black Tang is entirely jet black, often with a velvety or metallic sheen under strong lighting. Unlike other Zebrasoma species, which have a more oval body shape, the Black Tang has a more elongated snout, making it well-suited for picking algae from rock crevices. Its tail features a small white or bluish caudal spine, a typical defensive trait of surgeonfish.
While they lack the vibrant colours of other tangs, their solid black coloration makes them a unique and striking presence in any marine aquarium.
Natural Habitat and Behaviour
Black Tangs are deep-water fish, typically found at depths ranging from 20 to 40 metres in the Pacific Ocean, particularly around Christmas Island and the Line Islands. They are often solitary in the wild and prefer areas with strong currents and abundant algae growth.
In captivity, they exhibit typical tang behaviours:
• Constant grazing, feeding on algae throughout the day.
• Active swimmers, requiring plenty of open space.
• Can be territorial, especially toward other Zebrasoma tangs like Yellow, Purple, or Scopas Tangs.
Despite their territorial tendencies, they are generally peaceful with non-tang species and can coexist with a variety of reef-safe fish.
Tank Requirements and Water Parameters
Due to their active nature and large adult size, Black Tangs require a spacious, well-maintained tank.
• Minimum tank size: 500L+ (700L+ recommended for adults)
• Temperature: 23–26°C
• pH: 8.1–8.4
• Salinity: 1.020–1.025
• Water movement: Moderate to strong, mimicking their natural reef environment
• Filtration: High-capacity filtration and protein skimming recommended
Because they are herbivorous grazers, a tank with ample live rock and natural algae growth will help replicate their natural feeding behaviour.
Diet and Feeding
Black Tangs are primarily herbivorous, feeding on macroalgae and detritus in the wild. To maintain their health and coloration, they require a plant-based diet with occasional protein supplementation.
Recommended foods include:
• Dried seaweed (Nori) – Crucial for digestive health
• Spirulina-based flakes and pellets – Enhances immune function and colour vibrancy
• Fresh macroalgae – Such as chaetomorpha or gracilaria
• Occasional meaty foods – Enriched mysis shrimp, brine shrimp (as a supplement only)
Feeding multiple times per day is ideal, as they are natural grazers and need a consistent supply of nutrients. A lack of algae in their diet can lead to nutritional deficiencies and stress-related diseases.
Compatibility and Tank Mates
Black Tangs are generally peaceful but can be territorial, particularly with other Zebrasoma species. They are best housed as the only Zebrasoma tang in most aquariums unless introduced into a very large system (1000L+).
Best tank mates include:
✔ Clownfish
✔ Angelfish (both dwarf and large species)
✔ Wrasses (e.g., Fairy Wrasses, Halichoeres species)
✔ Gobies and blennies
✔ Other peaceful to semi-aggressive reef-safe fish
Avoid housing with:
❌ Other Zebrasoma tangs (Yellow, Purple, Sailfin) unless in a very large system
❌ Extremely aggressive tang species (e.g., Sohal Tang, Clown Tang)
❌ Slow-moving or delicate fish that may struggle to compete for food
If keeping multiple tangs, introduce them simultaneously in a large system to minimize territorial disputes.
Health and Disease Considerations
Despite their rarity, Black Tangs are fairly hardy if provided with a stable, high-quality environment. However, like all tangs, they are prone to:
• Marine ich (Cryptocaryon irritans) – Often caused by stress or poor water conditions. Quarantining new fish before adding them to the display tank is highly recommended.
• Head and Lateral Line Erosion (HLLE) – Usually linked to poor diet, vitamin deficiencies, or suboptimal water quality.
• Nutritional deficiencies – A diet lacking in marine algae can lead to faded coloration and digestive issues.
To keep them in optimal health:
✔ Provide a varied, algae-rich diet with plenty of seaweed.
✔ Ensure stable water conditions with high oxygenation.
✔ Quarantine new additions to prevent disease outbreaks.
Lifespan and Long-Term Care
With proper care, Black Tangs can live up to 10-15 years, making them a long-term commitment for experienced aquarists. Due to their rarity, price, and specific care needs, they are best suited for dedicated marine hobbyists with large reef tanks.
Why Choose a Black Tang?
✔ Rare and highly sought-after – A true showpiece fish.
✔ Excellent algae grazer – Helps control nuisance algae.
✔ Hardy and adaptable – Can thrive in well-maintained reef tanks.
✔ Unique coloration – A deep black fish that contrasts beautifully in a reef setting.