Black Longnose Tang

The Black Longnose Tang is an unmistakable saltwater fish prized for its nearly uniform jet-black coloration, tall sail-like fins, elongated snout, and contrasting white caudal spine at the base of the tail. Zebrasoma rostratum develops a bold, elegant profile that makes it a dramatic centerpiece in a large reef aquarium or fish-only aquarium.

Native to the Eastern Central Pacific, this marine aquarium fish occurs around the Line, Marquesas, Society, Tuamotu, and Pitcairn island groups, where it inhabits coral and rocky reef environments and spends much of its day browsing algae. Like other Zebrasoma tangs, it is an active swimmer and persistent grazer that benefits from mature rockwork and abundant open swimming space.

Although generally compatible with corals and most reef invertebrates, its semi-aggressive temperament can become more apparent around other tangs and similarly shaped surgeonfish. Its distinctive appearance, active grazing behavior, and uncommon presence in the aquarium trade make it an especially impressive choice for experienced marine aquarists with an appropriately sized system.

Quick Care Guide

Care Level: Moderate
Minimum Tank Size: 180 gallons
Temperament: Semi-aggressive
Diet: Herbivore
Reef Safe: Yes
Region: Eastern Central Pacific – Line, Marquesas, Society, Tuamotu, and Pitcairn island groups
Scientific Name: Zebrasoma rostratum

Tank Requirements

Provide a spacious, mature marine aquarium with strong filtration, good oxygenation, and plenty of horizontal swimming room. A large system with open swimming lanes is particularly important because this tang remains active throughout the day and requires substantial room as it reaches adult size.

Arrange live rock to create caves, arches, and sheltered areas while leaving generous open water for cruising. Established rockwork also provides natural surfaces for grazing on algae and biofilm. Moderate to strong, varied water movement is appropriate and helps maintain the high water quality expected by active surgeonfish.

A secure aquarium cover is recommended, particularly during acclimation or when the fish is startled. Avoid overly congested aquascapes that restrict swimming space or force the fish through narrow passages.

Diet and Feeding

In nature, the Black Longnose Tang feeds primarily on filamentous algae and other plant material growing across reef surfaces. Its captive diet should therefore remain strongly focused on marine-based vegetable foods.

Offer dried nori or other marine algae sheets daily, along with quality spirulina-based pellets, herbivore pellets, and prepared frozen foods formulated for marine grazers. Small amounts of mysis shrimp, enriched brine shrimp, and mixed frozen marine blends may also be accepted, but meaty foods should supplement rather than replace its algae-rich diet.

Multiple small feedings throughout the day are ideal when practical. Keeping algae sheets available regularly encourages natural grazing behavior and helps meet the nutritional demands of this active fish.

Temperament and Tankmates

The Black Longnose Tang is best classified as semi-aggressive. It is generally compatible with a broad range of appropriately sized marine fish but may become territorial toward other surgeonfish, especially members of the Zebrasoma genus or species with a similar body shape.

For most aquariums, keeping a single specimen is the safest approach. Mixing it with additional tangs should be reserved for very large systems with extensive swimming space, multiple feeding areas, and carefully planned introductions.

Suitable tankmates include many peaceful to moderately assertive reef fish that are not prone to harassing or fin-nipping tangs. Avoid combining it with highly aggressive species that may prevent it from feeding or establishing a comfortable territory.

Reef Compatibility

The Black Longnose Tang is considered reef safe and is generally an excellent choice for established reef aquariums. Healthy specimens normally spend their time grazing algae from rockwork rather than damaging corals.

It is not typically a threat to ornamental shrimp, crabs, snails, clams, or other common reef invertebrates. Maintaining a varied, algae-rich diet helps encourage normal grazing behavior and reduces the likelihood of inappropriate picking around the aquarium.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Stable water quality is more important than repeatedly adjusting the aquarium to chase exact numbers. Keep salinity, temperature, and pH consistent while maintaining low nutrient accumulation, strong aeration, and dependable biological filtration.

Common Considerations

• Requires a large aquarium with substantial open swimming space and mature rockwork for grazing.

• Can become territorial toward other tangs, particularly similarly shaped Zebrasoma species.

• Benefits from daily access to marine algae and frequent vegetable-rich feedings.

• Like all surgeonfish, it possesses sharp caudal peduncle spines and should be handled carefully.

• Provide stable, well-oxygenated water and allow the fish time to settle into sheltered areas during acclimation.

Care details were cross-checked against species distribution and maximum-size records as well as established aquarium husbandry guidance.