Redtooth Triggerfish Identification Guide
Identify this schooling reef fish by its deep blue-purple body and the red teeth visible up close.
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Key identification features
- Deep blue to purple body overall, sometimes appearing almost violet or indigo in bright sunlight
- Small red teeth, visible only on close inspection, giving the species its common name
- Elongated snout and a deeply forked, crescent-shaped tail
- Slender, compressed body reaching about 40 cm (16 in)
- Often seen in large, dense aggregations feeding on plankton in the water column, unusual behavior for a typically solitary or paired triggerfish
Common look-alikes
- Bluechin triggerfish (Xanthichthys auromarginatus): shows a blue chin patch and yellow-edged fins, and typically does not form the massive schools characteristic of the Redtooth.
- Black durgon (Melichthys niger): nearly black rather than blue-purple, and lacks the Redtooth's forked crescent tail shape and reddish teeth.
Where you'll see one
Common along Indo-Pacific reef drop-offs and current-swept outer slopes, where large schools hover well above the reef to intercept drifting zooplankton in the water column, quickly retreating into crevices and holes at the first sign of danger from passing predators.
Frequently asked questions
How do I recognize a Redtooth Triggerfish underwater?
Look for a slender blue-purple body with a deeply forked tail, often seen in large schools hovering above reef drop-offs to feed on plankton.
How can I tell it apart from a Bluechin Triggerfish?
The Bluechin shows a blue chin patch with yellow-edged fins and swims alone or in small groups, while the Redtooth is uniformly blue-purple and often forms large schools.