Blue-Lip Bristletooth Tang

The Blue-Lip Bristletooth Tang is a distinctive saltwater fish known for its rich orange-brown to dark brown body, fine blue horizontal lines, yellowish spotting around the head, and unmistakable blue lips. A narrow yellow ring around the eye adds further contrast, while juveniles can appear dramatically different, often displaying a bright yellow coloration before transitioning into the more complex adult pattern.

Ctenochaetus cyanocheilus is native to the western Pacific, ranging from the Ogasawara Islands through the Philippines and Indonesia to the Great Barrier Reef, New Caledonia, Samoa, and the Marshall Islands. It inhabits coral-rich inner and outer reefs, where it spends much of the day grazing algae and organic material from hard surfaces. Adults reach approximately 6.3 inches in standard length, making this one of the more manageable bristletooth tangs, though it still requires substantial swimming space.

Its constant grazing behavior, attractive coloration, and general compatibility with corals make this species an excellent candidate for established reef aquariums. Like other surgeonfish, it can become territorial toward similar tangs, particularly other members of the genus Ctenochaetus.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 90 gallons
Temperament: Semi-aggressive
Diet: Herbivore / Detritivore
Reef Safe: Yes
Region: Western Pacific
Scientific Name: Ctenochaetus cyanocheilus

Tank Requirements

Provide a mature marine aquarium with generous open swimming space and substantial live rock. This species is a continuous grazer and benefits greatly from established rock surfaces covered with natural biofilm, microalgae, and other organic growth.

Arrange rockwork to create sheltered caves and retreat areas while maintaining clear horizontal swimming lanes. Moderate to strong water movement, good oxygenation, and efficient filtration are recommended.

Because surgeonfish remain highly active throughout the day, aquarium footprint and swimming length are particularly important. A secure, stable aquascape also provides natural grazing territory and helps reduce stress.

Diet and Feeding

The Blue-Lip Bristletooth Tang is primarily an herbivorous and detritivorous grazer. Its specialized bristle-like teeth are adapted for brushing fine algae, biofilm, and organic material from reef surfaces.

Offer marine algae sheets or nori regularly, along with spirulina-based foods, high-quality herbivore pellets, and frozen marine herbivore blends. Small amounts of mysis shrimp, enriched brine shrimp, and other meaty foods may also be consumed, but algae-based foods should remain the foundation of the diet.

Multiple smaller feedings throughout the day are beneficial when practical. Mature live rock provides additional grazing opportunities between scheduled meals.

Temperament and Tankmates

This species is generally peaceful toward unrelated marine fish but may become territorial toward other surgeonfish, particularly other bristletooth tangs competing for the same grazing areas.

Suitable tankmates include wrasses, anthias, gobies, blennies, angelfish, and other appropriately sized reef fish. Mixing multiple Ctenochaetus species should be approached cautiously and is best attempted only in substantially larger aquariums.

Like all surgeonfish, it possesses a sharp caudal spine near the base of the tail and should be handled carefully.

Reef Compatibility

The Blue-Lip Bristletooth Tang is considered reef safe.

It does not normally consume coral tissue and is generally compatible with ornamental shrimp, crabs, snails, clams, and other established reef invertebrates. Most of its attention is directed toward algae, biofilm, and detritus growing on rock and other hard surfaces.

Its grazing behavior can be useful in managing certain forms of film algae, although it should not be relied upon as the aquarium's sole method of algae control.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Maintain stable water quality with good oxygenation and consistent salinity. Surgeonfish generally respond best to mature, well-maintained systems where rapid parameter swings are avoided.

Common Considerations

• Distinctive juvenile coloration: Young specimens may be bright yellow before developing the darker adult coloration, blue lines, and characteristic blue lips.
• Constant grazer: Mature live rock and regular algae-based feeding help support natural feeding behavior.
• Tang aggression: It may become territorial toward other surgeonfish, particularly other Ctenochaetus species.
• Active swimmer: Provide substantial horizontal swimming space despite its relatively moderate adult size.
• Reef compatible: Corals and established ornamental invertebrates are generally ignored.