Bluespine Unicorn Tang - Naso unicornis

Bluespine Unicorn Tang (Naso unicornis)

The Bluespine Unicorn Tang is a large and impressive marine surgeonfish recognised for its elongated body, blue-edged caudal spines and distinctive horn-like projection that develops on the forehead as the fish matures. Active, intelligent and constantly on the move, this species requires a very large, mature aquarium with extensive swimming space and excellent water quality. Its striking adult appearance and generally manageable temperament make it a rewarding choice for experienced marine aquarists able to accommodate its substantial adult size.

Common Name:
Bluespine Unicorn Tang, Bluespine Unicornfish, Unicorn Tang

Scientific Name (Latin):
Naso unicornis

Maximum Size:
Approximately 70 cm

Water Type:
Marine

Origin / Natural Habitat:
The Bluespine Unicorn Tang has a broad Indo-Pacific distribution and is found around coral reefs, reef slopes, channels and exposed coastal reef environments.

Adults typically occupy areas with strong water movement and abundant algal growth, while juveniles may occur in shallower reef and lagoon habitats.

Water Parameters:
Temperature: 24–26°C
pH Range: 8.1–8.4
Salinity: SG 1.024–1.026
Nitrate: Low and stable
Ammonia/Nitrite: 0 ppm

Temperament:
Peaceful to Semi-Aggressive

The Bluespine Unicorn Tang is generally less aggressive than many Acanthurus tangs, but adults can become territorial towards similarly shaped surgeonfish or other large grazing species.

It is best housed with robust, suitably sized marine fish and given enough space to establish a territory without constant competition.

Diet:
Herbivore / Algae Grazer

The Bluespine Unicorn Tang is primarily herbivorous and naturally grazes algae from reef surfaces.

In the aquarium, provide regular access to dried nori, marine algae sheets, spirulina-based foods, quality herbivore pellets and marine flakes.

A varied diet can also include occasional frozen mysis or other marine foods, but plant-based foods should remain the foundation of its long-term diet.

Minimum Tank Size:
Approximately 1,500 litres

This species can exceed 60 cm and may approach around 70 cm in length, so long-term accommodation requires an exceptionally large aquarium with extensive horizontal swimming space.

Behaviour & Activity:
The Bluespine Unicorn Tang is a highly active daytime swimmer and spends much of its time cruising through open water and grazing from rockwork.

As it matures, the characteristic horn-like projection on the forehead becomes increasingly prominent.

Adults are powerful swimmers and benefit from strong water movement, high oxygen levels and large unobstructed swimming areas.

Provide substantial rockwork for grazing and shelter, but avoid overcrowding the aquarium with structures that restrict movement.

Reef Safe:
Reef Safe

The Bluespine Unicorn Tang is generally considered reef safe and does not normally damage healthy corals, clams or established ornamental invertebrates.

Its natural feeding behaviour centres on algae and plant material, making it suitable for very large reef systems capable of supporting its adult size and activity level.

Special Requirements or Care Notes:
This species should only be purchased with its enormous adult size fully considered.

Provide a very large, mature aquarium with excellent filtration, strong oxygenation and extensive open swimming room.

Regular access to marine algae is essential, even when natural grazing is available.

Like other surgeonfish, the Bluespine Unicorn Tang possesses sharp defensive spines near the base of the tail. These can cause injury, so care should be taken during handling and aquarium maintenance.

Avoid keeping it with highly aggressive tankmates or multiple large tangs unless the aquarium provides exceptional space.

Surgeonfish can be susceptible to external parasites and stress-related disease, so careful acclimation, quarantine and stable water chemistry are strongly recommended.

Suitable for:
Experienced

Availability:
Availability can vary depending on season, collection area and supplier.

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Please note that Mother Nature is a wonderful thing, and variation in patterns and colours will occur — that is part of the unique beauty of these animals.