Dark Surgeonfish
Acanthurus blochii
Dark Surgeonfish (Acanthurus blochii) is a reef-associated surgeonfish of the Indo-Pacific, commonly seen in clear coastal waters and lagoons. It grazes on algae and detritus on coral and rocky reefs and is a minor local food fish in some areas.
Identification points
- Dark olive-brown to gray body with a blunt head profile
- Prominent pale/whitish band at the base of the tail with the scalpels on the caudal peduncle
- Typical surgeonfish oval body shape with a continuous dorsal fin and small mouth
Habitat
Shallow coral reefs, reef flats, lagoons, and sheltered outer reef slopes; usually in clear tropical marine water, often cruising near structure and grazing on algal-covered hard bottom.
Bait notes
Not a common targeted game fish. If taken by anglers, it may strike small algae imitations, tiny shrimp pieces, or finely cut natural baits near reef edges; small hooks and light tackle are required.
Behavior
Primarily diurnal and herbivorous/detritivorous, picking at algal films and benthic detritus. Often travels singly or in loose groups and retreats quickly to reef structure when disturbed.
Caution
Like many reef fish, it may be subject to local bag limits or reef-fish protections; check regulations. Avoid eating large individuals from tropical reefs where ciguatera risk can apply.
Fishing notes
Fish very close to reef structure, using light gear and minimal terminal tackle. Stealth matters in clear water; drift or present baits naturally over algal flats and reef margins. In many places it is better left un-targeted because of its reef role and modest table value.