Black Long-nose Tang (Zebrasoma rostratum) Care Guide
Zebrasoma rostratum, the longnose surgeonfish, is an all-black Pacific tang with a protruding snout that grazes filamentous algae on lagoon and seaward reefs.
Compiled by Aquairi from published sources · Published · Updated
Overview
Zebrasoma rostratum, the longnose surgeonfish, is a Pacific tang of the family Acanthuridae. Its body is dark brown to nearly black with faint bluish lines following the scale rows, and it has a distinctly protruding snout used to reach algae in crevices.
Taxonomy
- Family: Acanthuridae
- Genus: Zebrasoma
- Scientific name: Zebrasoma rostratum
Habitat
The species occurs in the eastern central Pacific around the Line, Marquesas, Society and Tuamotu islands to the Pitcairn group. It is reef-associated, inhabiting lagoon and seaward reefs, usually at depths of 8-35 m.
Tank requirements
- Minimum tank volume: 700 L
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Specific gravity: 1.024-1.026
- Carbonate hardness (dKH): 8-12
- Water flow: high
- Adult size: up to about 21 cm
- Lifespan: 10-25 years
Diet
Its small, numerous pharyngeal teeth indicate a diet consisting mainly of filamentous algae. In the aquarium it requires plentiful algae or dried marine algae offered several times daily.
Compatibility
It can be kept with wrasses, clownfish, angelfish and sturdy triggers. Other tangs, particularly those of similar shape, should be avoided in smaller tanks.
Reef compatibility
The black long-nose tang is reef-safe and grazes algae. It needs a spacious reef aquarium with strong flow.
Breeding
Aquarium breeding is not established and is considered an expert undertaking.
Black Long-nose Tang Breeding Guide
Overview
Zebrasoma rostratum, the black long-nose tang, is a Central Pacific surgeonfish of the Line, Marquesas, Society and Tuamotu islands to the Pitcairn group, reaching about 21 cm. It has an elongated snout and feeds mainly on filamentous algae, as indicated by its numerous small pharyngeal teeth, on lagoon and seaward reefs. As an acanthurid it reproduces by pelagic broadcast spawning. IUCN status is Data Deficient.
Sexing
The uniformly dark body offers no external sexual difference, and the sexes cannot be told apart by colour or markings. Following the surgeonfish pattern, sex is evident only through spawning behaviour as fish ascend to release gametes, so deliberate sexing is impractical in the aquarium.
Conditioning
As a filamentous-algae grazer, this tang needs continuous access to algae and frequent feeding to remain in condition. A large, stable warm-water reef system is required simply to maintain the fish well, well before any consideration of reproductive condition.
Breeding Setup
Because it is a broadcast spawner releasing eggs into open water, reproduction depends on water-column space rather than a nest. No aquarium breeding setup is documented for this uncommon species, so the description here reflects the general acanthurid pattern rather than a proven home protocol.
Spawning Behavior & Trigger
Surgeonfish reproduce by rising in the water column, where pairs or groups release eggs and sperm for external fertilisation and the eggs disperse as plankton. No species-specific captive spawning trigger is documented for the black long-nose tang.
Egg & Fry Care
There is no parental care; the pelagic eggs drift and hatch into the transparent acronurus larva characteristic of the family, which lives in open water for an extended period before settling and transforming into a juvenile. Rearing this stage requires specialised techniques unavailable in a home tank.
Common Challenges
As with other tangs, the long pelagic acronurus stage is the principal barrier to captive production, and this species is uncommon in the trade and rarely kept in groups, making spawning attempts unlikely at home. To date only a handful of surgeonfish, led by the yellow tang, have been raised to settlement, and Zebrasoma rostratum is not among them.