Orange-shoulder Tang Care Guide
Acanthurus olivaceus is an Indo-Pacific surgeonfish with a striking orange shoulder bar, reaching 35 cm and grazing on detritus and algae.
Overview
Acanthurus olivaceus, the orange-shoulder surgeonfish, is a deep-bodied, laterally compressed surgeonfish of the family Acanthuridae. Adults are greyish-brown and carry a distinctive orange bar with a purplish-black margin behind the top of the gill cover, while juveniles are plain yellow. According to FishBase, it reaches a maximum total length of 35 cm.
Taxonomy
- Family: Acanthuridae
- Genus: Acanthurus
- Scientific name: Acanthurus olivaceus
- Described by: Bloch & Schneider, 1801
Habitat
The species is marine and reef-associated across the Pacific and eastern Indian Ocean, from Christmas Island and the Cocos-Keeling Islands to the Hawaiian and Tuamotu islands, north to Japan and south to Lord Howe Island. Adults inhabit seaward reefs over bare rock or mixed rubble and sand, recorded by FishBase at depths of 3-46 m, while juveniles occupy protected bays and lagoons in as little as 3 m.
Tank requirements
- Minimum tank volume: 800 L (211 gal)
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Specific gravity: 1.024-1.026
- Carbonate hardness: 8-12 dKH
- Strong water flow
- Lifespan: 10-25 years in captivity (FishBase reports up to 33 years in the wild)
Diet
Acanthurus olivaceus is a herbivorous grazer. In the wild, adults consume the surface film of detritus, diatoms and fine filamentous algae covering sand and bare rock. In aquaria it should be offered marine algae and dried seaweed multiple times daily to support its continuous grazing behaviour.
Compatibility
This is a semi-aggressive, diurnal mid-water swimmer. Adults are typically solitary but sometimes join mixed-species grazing schools with parrotfish and other tangs. Suitable tankmates include wrasses, clownfish, angelfish and sturdy triggerfish. Other tangs, especially those of similar body shape, should be avoided in smaller systems.
Reef compatibility
The orange-shoulder tang does not consume coral and is generally considered reef-safe, grazing nuisance algae from rock and substrate. Stable carbonate hardness of 8-12 dKH and specific gravity of 1.024-1.026 support both the fish and reef invertebrates.
Conservation status
IUCN Red List: Least Concern, assessed in 2010 via FishBase, reflecting a wide Indo-Pacific distribution.