Tennenti Tang (Acanthurus Tennenti)

Also Known As: Lieutenant Tang, Tennenti Surgeonfish,

Compatibility and Behavior
The Tennenti Tang (Acanthurus tennentii) is an elegant, active grazer with one of the prettier color stories in the genus. Juveniles and smaller specimens tend to show a soft bluish-gray to silvery body with a pale face and subtle blue accents along around the tail, while adults firm up into a more defined gray-blue with a darker facial mask and that distinctive "cheek line" that lends the fish its officer-like look, hence the Lieutenant Tang nickname. Under strong reef lighting you'll often catch faint spotting and a gentle iridescent sheen along the flanks as it glides through open water. Temperament-wise, Tennentis tend to be peaceful to semi-aggressive and are often a touch more easygoing than some of the bolder Acanthurus species, particularly when they aren't cramped and have plenty to graze on. They're typically regarded as reef safe, spending most of the day browsing film and filamentous algae off rock and hard surfaces rather than corals or ornamental inverts, though an underfed or stressed individual may occasionally posture or nip. With thoughtful stocking, they usually coexist well with tankmates like clownfish, fairy and flasher wrasses, Anthias, gobies, and differently shaped tangs, as long as there's enough space and plenty of hiding options.

Aquarium Requirements
Tennenti Tangs love long, open swimming runs and mature rockwork, so they do best in established systems with generous horizontal space. For tiny to medium specimens in the 1 to 3.5 inch range, a tank around 120 gallons with a long footprint is a reasonable starting point, with larger volumes strongly preferred for Lg and XL fish and for long-term comfort. Aquascape with a balance of open water columns and solid, mature live rock that provides natural grazing surfaces, arches, and shaded caves where the fish can retreat and sleep at night. Strong, well-oxygenated flow and robust filtration help support their active lifestyle and keep water quality clean and stable. Regular feedings of nori, marine algae, and varied herbivore foods will help maintain their body weight, color, and calm demeanor while keeping aggression toward tankmates in check.

Specifications
Approximate Size: Tiny: 1–1.5", Sm: 1.5–2.5", Md: 2.5–3.5", Lg: 3.5–4.5", XL: 4.5–6"
Diet: Primarily herbivorous. Marine algae, nori, and spirulina-based foods, with supplemental frozen mysis shrimp
Origin: Indo-Pacific reef regions
Care Level: Intermediate
Reef Safe: Yes
Temperament: Peaceful to semi-aggressive; may be territorial toward other tangs and similar grazers
Minimum Tank Size: Smaller specimens (Tiny/Sm) can start around 90 gallons, but plan to scale up to 120 gallons or more as they grow