Thompsonii Tang (Acanthurus Thompsoni)

Thompson’s Tang (Acanthurus thompsoni)

The Thompson’s Tang, also known as the Night Surgeonfish or Thompson’s Surgeonfish, is a unique departure from the typical colorful Tang. While most Acanthurus species are prized for their bright yellows, oranges, or blues, the Thompsonii is the "stealth fighter" of the family. It is a sleek, monochromatic fish that appeals to hobbyists looking for a sophisticated, natural look rather than a neon centerpiece.

Key Information

• Common Names: Thompson's Tang, Night Surgeonfish, White-tail Surgeonfish

• Scientific Name: Acanthurus thompsoni

• Origin: Wide Indo-Pacific (East Africa to Hawaii)

• Max Size: 25 cm (approx. 10 inches)

• Lifespan: 10–15 years

• Temperament: Peaceful to Semi-aggressive (One of the most peaceful Acanthurus)

• Diet: Omnivore – Primarily a planktonivore (unique for a Tang)

• Care Level: Moderate

Appearance & Identification

The Thompson’s Tang is defined by its understated, "velvet" appearance:

• The Body: A uniform, dark chocolate-to-black color across the entire body. Under certain lighting, it can show a deep purplish hue.

• The Tail: Features a stark, snow-white caudal fin (tail), which provides a dramatic contrast against its dark body.

• The "Spot": There is often a small, dark spot at the base of the pectoral fin and a dark streak near the gill cover.

• The Eye: Often appears very dark, blending into the head for a completely "blacked-out" aesthetic.

Behaviour: The "Open Water" Tang

• Planktonivore: Unlike the Scopas Tang or Powder Brown, which spend their days grazing on rocks, the Thompsonii is a "water column" feeder. In the wild, it swims high above the reef to catch drifting zooplankton.

• Peaceful Nature: Because it doesn't compete for "algae territory" on the rocks as fiercely as other Tangs, it is generally much more tolerant of tank mates.

• Swimming Style: It is a powerful, streamlined swimmer that needs a lot of "runway" space. It moves with a constant, shark-like grace.

• Reef Safe: 100% Reef Safe. It will never bother corals or invertebrates.

Ideal Tank Setup

• Tank Size: A minimum of 380L–475L (100–125 Gallons). Due to its size and active swimming habits, a 5-foot or 6-foot tank is highly recommended.

• Flow: They thrive in high-flow environments with plenty of oxygenation, mimicking the reef drop-offs where they live.

• Dietary Needs: While it will graze on some algae, its primary diet should be meatier foods. Offer frozen mysis, enriched brine shrimp, and finely chopped seafood. You should still provide Nori (seaweed) to ensure it gets the vitamins common to all surgeonfish.

• Open Space: Keep the middle and upper layers of the tank clear of rockwork to allow for its high-speed swimming.

Why Choose the Thompson’s Tang?

The Thompsonii is for the hobbyist who wants a "Naturalistic" display. It looks incredibly impressive in a large school (in very large tanks) or as a dark silhouette that allows the colors of your corals to be the main focus. It is a "low-drama" Tang that adds a sense of scale and movement to a large reef.