Description

The Convict Tang (Acanthurus triostegus) is a peaceful, active herbivorous surgeonfish known for its distinctive black vertical stripes and constant grazing behavior. It’s one of the few tangs that can tolerate other tangs more readily, making it a popular choice for larger reef and fish-only systems.

🐟 Convict Tang Description:

• Scientific Name: Acanthurus triostegus

• Common Names: Convict Tang, Convict Surgeonfish

• Origin: Indo-Pacific (Hawaii, Great Barrier Reef, Red Sea, East Africa)

• Size: Up to 8 inches (20 cm)

• Coloration: Pale white to light yellow body with 6 bold black vertical bars; streamlined body and small mouth designed for grazing algae

• Temperament: Peaceful (for a tang), social in the wild

• Lifespan: 5–10 years in captivity

🧪 Tank Requirements:

• Minimum Tank Size: 125 gallons or larger (due to adult size and activity level)

• Water Temperature: 74–80°F (23–27°C)

• pH Level: 8.1–8.4

• Specific Gravity: 1.020–1.025

• Water Hardness: 8–12 dKH

• Aquascape: Lots of open swimming space with live rock for grazing

🥬 Diet:

• Herbivorous grazer – eats large amounts of algae:

  • Naturally grazes on turf algae, macroalgae, and film algae

  • Supplement with dried nori (seaweed), spirulina flakes, and algae-based pellets

  • Will accept some mysis or brine, but protein should be minimal

Feed multiple times daily with an emphasis on plant-based foods to prevent malnutrition.

🤝 Compatibility:

• Reef Safe: Yes – completely safe with corals and invertebrates

• Tankmates:

  • Peaceful to semi-aggressive fish

  • Usually less aggressive than other tangs, even tolerant of multiple tang species if introduced carefully

  • Can be kept in groups in very large tanks (300+ gallons), but one per tank is common

⚠️ Special Notes:

• Needs plenty of swimming space – very active

• Can become aggressive in smaller tanks or if underfed

• Like all tangs, has a sharp “scalpel” at the base of the tail – can injure others if provoked

• Quarantine new specimens if possible; tangs are prone to marine ich

• Stable, well-oxygenated water with strong flow preferred

📝 Summary: