Convict Tang

The Convict Tang (Acanthurus triostegus) is a reef-safe algae grazer that helps keep rockwork and hard surfaces clear of fine, fast-growing algae. Its pale body with bold vertical black bars and soft yellow highlights gives it the classic “convict surgeonfish” look seen across the Indo-Pacific.

What You’ll Observe:

• Cruises steadily through open water, then makes quick loops back to the rockwork to graze
• Spends much of the day “picking” along flat rock faces and high-light areas where algae films build up
• Often moves confidently around other fish, especially once it has a regular feeding routine
• At lights-out, settles into the rockwork and reappears soon after the tank brightens

To do well long-term, provide strong, stable filtration with plenty of open swimming room and rock surfaces for grazing. Offer sheet algae plus spirulina-based foods in multiple small feedings, and place food in more than one spot so it can eat without being crowded. In larger systems, groups can be introduced together for a more natural, coordinated swimming pattern.

Do Convict Tangs actually school in aquariums?
They can form a loose “pack” when kept as a small group, especially if introduced at the same time. In many home tanks they still behave like active individuals that happen to graze in the same areas.

Why does my Convict Tang ignore nori on a clip?
Some focus on grazing natural films first and take prepared foods more consistently after they learn your feeding schedule. Trying smaller strips, a different clip location, or attaching algae to a rock often helps.

Is it normal for the bars to look lighter at certain times of day?
Yes—many keepers notice the pattern can look softer when the fish is resting, adjusting to new lighting, or settling in for the night, then sharpens again when active.

Will it “follow” other tangs around the tank?
It’s common to see them trail other grazers and join whatever area is being picked clean. This usually looks like coordinated grazing rather than true pairing behavior.

Will a Convict Tang eat decorative macroalgae in the display?
They often sample a variety of algae types, so decorative macros may get grazed as new growth appears. If you want macroalgae to stay untouched, keeping it in a refugium is the most consistent approach.

Each fish is checked for strong appetite and activity before we approve it for your tank.