Bristletooth Two Spot Tang (Ctenochaetus binotatus) | Live Saltwater Reef Fish

The Bristletooth Two Spot Tang (Ctenochaetus binotatus), also called the Two Spot Surgeonfish or Pencilled Bristletooth, is a peaceful, reef-safe tang named for the two distinctive dark spots near the base of its tail. Its dusky brown body is dusted with fine blue-white speckles that intensify with maturity, giving it a subtle, sophisticated look that pops against live rock. Like its Tomini cousin, it's one of the most easygoing tangs in the hobby — a hard-working algae grazer that won't pick at corals and rarely starts fights.

Care level is intermediate, mainly because — like all tangs — it needs swimming room and a steady supply of micro-algae to thrive long-term.

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• Tank Size: 75 gallons minimum — needs swimming room and grazing surface area; 90+ gallons preferred long-term
• Temperature: 72–78°F (22–26°C)
• Salinity: 1.020–1.025 sg (specific gravity)
• pH: 8.1–8.4
• dKH: 8–12
• Diet: Herbivore — marine algae sheets (nori), spirulina-based pellets, frozen mysis, brine shrimp, and high-quality herbivore preparations. Feed multiple small meals per day.
• Temperament: Peaceful — one of the more docile tangs; non-aggressive toward most tankmates
• Reef Compatible: Yes — bristletooth grazer that won't nip corals, clams, or invertebrates
• Max Size: ~7 inches (18 cm)

Two Spot Bristletooth Tangs are reef-safe and one of the more peaceful tangs available, making them excellent community reef inhabitants. Like all tangs, only one tang per tank is recommended unless the tank is very large (180+ gallons) and additional tangs are added simultaneously and from different genera.

Good tank mates: Clownfish, gobies, blennies, cardinalfish, dwarf and pygmy angels, peaceful wrasses, firefish, anthias, peaceful damsels, and most reef invertebrates (shrimp, snails, hermit crabs, corals).

Avoid: Other Bristletooth tangs (especially Tomini Tang or Kole Tang in smaller tanks), aggressive triggers, large angels that pick at corals, and any aggressive or predatory fish that could harass a slim, peaceful grazer.

• Marine algae sheets & herbivore foods — primary diet for daily grazing
• Reef salt mixes — keep salinity stable during water changes
• Reef additives & supplements — alkalinity, calcium, and trace elements
• Water care & conditioners — for stable parameters
• Water testing kits — monitor reef parameters regularly

How is this different from a Tomini Tang?
They're closely related Bristletooths in the same genus and behave similarly — peaceful, reef-safe algae grazers. The Two Spot has the namesake pair of dark dorsal/ventral spots near the tail; the Tomini has bright yellow fin tips. Two Spots also tend to grow slightly larger (~7" vs ~6"). Both are excellent first tangs.

Is it reef safe?
Yes. As a bristletooth grazer it eats film algae, diatoms, and detritus from rock and sand surfaces. It will not pick at corals, clams, or invertebrates.

What does it eat?
Primarily an herbivore that grazes constantly. Offer marine algae sheets (nori) clipped to the glass daily, plus spirulina pellets, frozen mysis, and quality herbivore preparations. Adequate algae and varied feeding are critical to long-term health.

What tank size do I need?
75 gallons is the practical minimum, with 90+ gallons recommended for long-term housing in a mature reef. They're active, fast swimmers and need linear length to cruise.

Can I keep it with another tang?
In most home aquariums, only one tang per tank is recommended. In tanks 180 gallons or larger, multiple tangs from different genera can sometimes coexist when added together — but Two Spots are best kept as the only Bristletooth.