Orangeblotch Surgeonfish
Acanthurus olivaceus
Orangeblotch Surgeonfish (Acanthurus olivaceus) is a tropical reef surgeonfish of the Indo-Pacific, often showing a bright orange patch on the rear body as juveniles and subadults. It grazes on algae over reef flats and slopes; adults are less often targeted by anglers than many nearshore food fishes.
Identification points
- Oval, laterally compressed body with a long continuous dorsal fin
- Distinct orange blotch on the rear half of the body, especially on juveniles and subadults
- Small mouth and a narrow caudal peduncle with tail-base scalpel blades
Habitat
Clear tropical coral and rocky reefs, reef flats, surge channels, and outer reef slopes; juveniles often shelter in shallow lagoons and protected reef areas, while adults range more broadly along reefs and drop-offs.
Bait notes
Not a common sport target. If angled for, small algae-imitating baits, nori strips, and tiny pieces of shrimp or squid can work; small reef jigs or micro-soft plastics may also take bites from curious fish.
Behavior
Primarily an algal grazer that feeds during the day while moving in loose groups or pairs. It is wary, quick, and uses reef structure for cover; like other surgeonfish, it can become territorial around feeding areas.
Caution
Sharp scalpels at the tail base can cut hands; handle with care. Reef fish from tropical areas may carry ciguatera toxin in some locations, so local consumption advisories matter.
Fishing notes
Use very light tackle, small hooks, and stealth around shallow reefs and lagoons. Cast upcurrent near coral edges and feed drifts naturally; avoid snagging the reef and release quickly if caught, as surgeonfish are delicate in handling.