Lieutenant Surgeon

Species Profile

• Scientific Name: Acanthurus tennetti
• Common Name: Lieutenant Surgeon / Doubleband Surgeonfish / Tennenti Tang
• Adult Size: Up to 10–12 inches (25–30 cm)
• Life Expectancy: 10–15 years in captivity with proper care
• Habitat:
  • Found in coastal coral reefs and lagoon areas
  • Native to the Indo-Pacific, from East Africa to Fiji

  • Frequently inhabits clear outer reef slopes and reef crests

Tank Requirements

• Minimum Tank Size: 125 gallons (475 liters) or larger
  Needs ample swimming space and rockwork for grazing
• Ideal Temperature: 75–82°F (24–28°C)
• pH Range: 8.1–8.4
• Water Hardness: 8–12 dKH
• Temperament:
  • Generally peaceful, though may be territorial with other tangs
  • Best kept with non-aggressive tank mates

  • Can coexist with other species if introduced properly

Diet & Nutrition

• Primarily herbivorous, grazing on algae and plant matter
• Offer:
  • Dried seaweed (nori) attached to a veggie clip
  • Spirulina-based flakes or pellets
  • Occasional mysis or brine shrimp for protein

• Must be fed multiple times daily to maintain energy and immunity

Breeding & Spawning

• Very rare in captivity
• In the wild:
  • Spawn in pairs or groups
  • Broadcast spawners, releasing gametes into open water

  • No parental care after spawning

Appearance

• Body is a bluish-gray to silver color
• Features a distinctive black band from the mouth through the eye
• Second black stripe often runs vertically behind the gill plate
• Yellow highlights near the caudal peduncle and tail fin

• Tail is typically forked with white or yellow edging

Distinctive Features

• Named “Lieutenant” due to the shoulder stripes resembling military insignia
• Has a sharp scalpel-like spine near the tail, used for defense
• Active swimmer; requires a large tank with open swimming areas

• Helps control algae in reef tanks by constant grazing