Powder Black Tang Care Guide
Acanthurus nigricans is an Indo-Pacific surgeonfish with a bluish-black body and white cheek patch, feeding on filamentous algae and reaching about 36 cm.
Compiled by Aquairi from published sources · Published · Updated
Overview
Acanthurus nigricans, the whitecheek surgeonfish, is an oval-bodied member of the family Acanthuridae. It is overall bluish-black with a white patch below the eye, yellow bands at the dorsal and anal fin bases, a yellow ring around the caudal spine and a white caudal fin with a yellow submarginal band. FishBase records a maximum fork length of 36 cm.
Taxonomy
- Family: Acanthuridae
- Genus: Acanthurus
- Scientific name: Acanthurus nigricans
- Described by: Linnaeus, 1758
Habitat
The species is marine, reef-associated and non-migratory, occurring in the eastern Indian Ocean (Cocos-Keeling and Christmas Islands) and across the Pacific from the Ryukyu Islands and Great Barrier Reef to the Hawaiian Islands and French Polynesia, as well as the Revillagigedo, Cocos and Galapagos islands and the Mexican coast. It inhabits hard-substrate areas of clear lagoon and seaward reefs, with FishBase recording depths from 0 to 67 m, usually 2-67 m. Juveniles shelter among large corals.
Tank requirements
- Minimum tank volume: 700 L (185 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
Diet
Acanthurus nigricans is a herbivore that feeds on filamentous algae in the wild. In aquaria it should be offered marine algae and dried seaweed multiple times daily to support its constant grazing.
Compatibility
A semi-aggressive, diurnal mid-water swimmer, the species is monogamous and territorial in the wild, occurring solitarily or in groups. Wrasses, clownfish, angelfish and sturdy triggerfish make suitable tankmates, while other tangs of similar shape should be avoided in smaller systems. FishBase notes it can live up to 34 years.
Reef compatibility
The species does not eat coral and is considered reef-safe, grazing nuisance algae from rock. Maintain carbonate hardness of 8-12 dKH and specific gravity of 1.024-1.026 for corals and invertebrates.
Conservation status
IUCN Red List: Least Concern, assessed in 2010 via FishBase.
Powder Black Tang (Acanthurus nigricans): Breeding Guide
Overview
The Powder Black Tang, Acanthurus nigricans, occurs in the eastern Indian Ocean at the Cocos-Keeling and Christmas Islands and across the Pacific from the Ryukyus and Great Barrier Reef to Hawaii and French Polynesia, with eastern Pacific records at the Revillagigedos, Cocos, Galapagos and the Mexican coast. FishBase gives a maximum fork length of 36 cm and a depth range of 0 to 67 m.
It is an algae grazer found solitarily or in groups, with shy juveniles sheltering among large corals. There are no records of this species being bred in captivity.
Spawning Behavior & Trigger
FishBase notes that monogamous mating is observed in A. nigricans as both facultative and social, and that adults are territorial. As in the genus generally, fertilization is external: gametes are broadcast into the open water column above the reef, typically at dusk and often around lunar phases when currents help disperse the eggs.
Even where a male and female associate, spawning is a brief open-water release rather than a guarded nest. Detailed species-level spawning timing for A. nigricans is not given in the consulted sources.
Egg & Fry Care
Eggs are pelagic and float away on the current. They hatch into transparent acronurus larvae that occupy the plankton for an extended period, which in surgeonfishes can last more than 39 days before the larvae settle.
Because the larvae must drift and feed in the open ocean, they cannot be reared in a home aquarium. Larval culture of surgeonfishes is limited to dedicated research aquaculture.
Common Challenges
- Even a facultatively monogamous pair spawns in open water, leaving no eggs to collect.
- Territorial aggression toward similar fish complicates keeping a compatible pair.
- The long pelagic acronurus stage cannot be supported on aquarium plankton.