Convict Tang

Species Profile

• Scientific Name: Acanthurus triostegus
• Common Name: Convict Tang (also called Convict Surgeonfish)
• Adult Size: 6–8 inches (15–20 cm)
• Life Expectancy: 5–10 years in captivity (longer in the wild with ideal conditions)
• Habitat:
  • Native to Indo-Pacific regions, including Hawaiian Islands, Red Sea, Australia, and Japan
  • Found in shallow reef flats, lagoons, and rocky coastal areas

  • Usually seen in large schools, especially in the wild

Tank Requirements

• Minimum Tank Size: 75 gallons (284 liters)
  Larger if kept in a group
• Ideal Temperature: 72–82°F (22–28°C)
• pH Range: 8.1–8.4
• Water Hardness: 8–12 dKH
• Temperament:
  • Generally peaceful and reef-safe
  • Can become territorial with similar species

  • Best kept either singly or in odd-numbered groups (3 or more) to reduce aggression

Diet & Nutrition

• Primarily herbivorous
• In the wild: grazes on algae growing on rocks and reefs
• In captivity, offer:
  • Nori (dried seaweed)
  • Spirulina-enriched flakes or pellets
  • Vegetable-based frozen foods

  • Occasional protein treats like mysis shrimp (but minimal)

Breeding & Spawning

• Very rarely bred in home aquariums
• In the wild:
  • Form spawning aggregations
  • External fertilization — eggs and sperm released into the water

  • No parental care; planktonic larvae hatch and drift before settling

Appearance

• Bright white or pale yellowish body
• Six bold black vertical stripes resembling a prison uniform — hence the name “Convict” Tang
• Streamlined body with scalpel-like spines near the tail base

• Fins are often translucent

Distinctive Features

• Iconic striped pattern
• Active swimmers, often seen grazing on algae throughout the day
• Hardy, social, and great for community and reef tanks

• Considered a great beginner saltwater tang due to its peaceful nature and algae-eating habits