Tenenti Tang (Acanthurus tennenti)

The Tenenti Tang, also widely known as the Lieutenant Tang, Vampire Tang, and Doubleband Surgeonfish, is one of the more distinctive and underappreciated large tang species available to serious reef keepers. Adults display a tan to grey body with darker lines outlining the body, two prominent black markings behind the eyes and at the scalpel that are outlined in brilliant electric blue, and a forked tail that develops vivid blue and white colouration as the fish matures. The twin dark marks on the shoulder are what earn this fish its two most evocative common names: to some hobbyists they resemble the rank insignia of a military lieutenant, to others the canine teeth of a vampire. This species also undergoes a notable colour transformation from juvenile to adult; juveniles display a warm yellowish-gold colour that gradually develops into the complex adult pattern, making it a fascinating fish to grow out over time. It is a large, active, and powerful swimmer suited exclusively to spacious, mature systems.

Why we love it

• A genuinely striking and unusual-looking tang with a colour pattern that improves and deepens dramatically from juvenile to adult
• Particularly sought after for large reef aquariums where it works to keep excess algae growth in check, including hair algae, without bothering delicate corals or smaller peaceful reef fish
• Active and entertaining with a bold swimming style that uses the full water column, making it a constant presence in any large display
• Fully reef safe with corals and ornamental invertebrates when well fed
• A rewarding long-term species with a lifespan that can exceed a decade in a properly maintained system

Suggested parameters

• Temperature: 24 to 26°C (75 to 79°F)
• Salinity: 1.025 to 1.026 SG
• pH: 8.1 to 8.4
• Alkalinity: 8 to 10 dKH
• Calcium: 400 to 450 ppm
• Magnesium: 1250 to 1400 ppm
• Nitrate: Under 20 ppm; clean, stable water with low nitrates is important for immune health
• Strong, varied water current and turbulence are preferred, along with high dissolved oxygen levels; surface agitation and good flow are non-negotiable for this active species

Care and temperament

• Difficulty: Moderate
• Temperament: Semi-aggressive; aggressive toward other tangs and surgeonfish, particularly those of similar size and body shape; peaceful and non-confrontational toward most other reef fish species
• Reef safe: Yes; may occasionally pick at large polyp stony corals if underfed, but a well-fed specimen in a system with ample natural algae for grazing is unlikely to cause issues
• Minimum tank size: 680 litres (180 gallons); this is a large, fast-moving fish that needs real swimming room
• Requires large amounts of live rock to provide territories within the aquascape alongside wide open swimming lanes
• Can be kept alongside other tang species in very large systems but should only be housed with similarly shaped surgeonfish when adequate territory is available for each
• A tight-fitting lid is essential; tangs are active and confirmed jumpers

Diet

The Tenenti Tang is a dedicated herbivore and a plant-heavy diet is the foundation of its long-term health, colour, and immune function.

• Nori and dried seaweed sheets on a clip or tied to a rock (daily feeding is ideal)
• Spirulina-based pellets and flakes
• Frozen herbivore blends
• Quality prepared marine algae foods; herbivore-specific frozen formulas are excellent supplements
• Foods soaked in vitamin supplements, particularly vitamin C, are strongly recommended to support immune function, lateral line health, and parasite resistance
• Meaty foods such as mysis shrimp can be offered occasionally for variety but should never form the basis of the diet
• Feed at least two to three times daily; constant access to algae and seaweed between feedings is ideal for a fish that grazes continuously in the wild

Compatibility and tankmates

• Excellent with clownfish, angelfish, wrasses, dartfish, gobies, and most peaceful to moderately assertive reef fish
• Aggressive toward other tangs; introduce the Tenenti Tang before or simultaneously with other surgeonfish species to minimise territorial conflict
• Avoid keeping with similarly shaped large Acanthurus tangs unless the system is very large with genuine territorial separation
• Compatible with all corals, ornamental shrimp, and reef invertebrates when well fed
• A tight-fitting lid is recommended; tangs can jump, particularly during the first weeks of acclimation

Health and acclimation notes

Like all Acanthurus tangs, the Tenenti Tang carries a relatively thin slime coat and is susceptible to marine ich, marine velvet, and lateral line disease, particularly during the stress of shipping and introduction. Maintaining the highest possible water quality and offering a varied diet rich in nutritious marine-based algae, soaked in vitamins, is the most effective long-term defence against skin parasites and fin erosion in this species. Quarantine before introduction to a display system is strongly encouraged. A varied, algae-heavy diet begun immediately upon acclimation is critical to building a robust immune response in new arrivals.

What you are buying

• You will receive: 1 Tenenti Tang (Acanthurus tennenti)
• Juveniles are primarily yellowish-gold and will develop the full adult pattern of tan-grey body, twin black shoulder marks with electric blue outlines, and forked blue-and-white tail over time
• Colouration and pattern definition intensify significantly with age and a strong algae-based diet

Slow acclimation is recommended. Quarantine before introduction to your display is strongly encouraged. A tight-fitting lid is essential.