Brown tang
Zebrasoma scopas
The Scopas Tang presents a mesmerizing ombré of dark brown fading to warm yellow. A resilient and highly effective herbivore, it continuously patrols the rockwork to keep marine macroalgae tightly trimmed.
Water Temperature
24 - 28 °C
pH Value
8.1 - 8.4
Water type
Marine
Tank level
All levels
Adult size
20 cm
Minimum tank volume
>= 300 L
Minimum group
>= 1
KH
8 - 12 dKH
Species description
Geographical Origin and Habitat: Zebrasoma scopas, the brown tang or twotone tang, is widely distributed across the tropical Indo-Pacific, from the Red Sea and East Africa to the Tuamotu Islands, and north to southern Japan and south to the Great Barrier Reef. It inhabits coral-rich lagoons and seaward reefs at depths ranging from 1 to 60 meters, foraging on rocky substrates.
Taxonomy and Morphology: A member of the Acanthuridae family, it has a disc-shaped, laterally compressed body with a protruding snout designed for grazing algae in tight crevices. Like other Zebrasoma, it features large sail-like dorsal and anal fins and a sharp caudal spine on each side of the tail. Adults reach up to 20 cm (8 inches).
Social Behavior: It is a highly active and territorial fish, especially towards conspecifics or other tangs with similar body shapes. It is generally peaceful towards unrelated species. It spends its daylight hours constantly moving around the tank, grazing on algae-covered rocks.
Coloration and Sexual Dimorphism: The body color displays a gradient transitioning from yellowish-brown on the front half to dark brown or nearly black on the rear. Fine light-blue dots and wavy lines cover the body. Sexual dimorphism is not externally visible, although males are typically slightly larger.
Care, breeding and tankmates
Aquarium Setup: An aquarium of at least 70 gallons (250-300 liters) is required to provide adequate swimming space. The tank should feature plenty of mature live rock for grazing and hiding, arranged to allow for open water movement and pathways. A covered aquarium is recommended.
Diet and Feeding: Primarily herbivorous. Its diet must focus heavily on marine algae. Feed dried seaweed (nori) sheets attached to a clip, spirulina, and high-quality herbivore flakes or pellets daily. Small amounts of frozen mysis or brine shrimp can be offered to supplement protein intake.
Water Quality: Requires clean, well-oxygenated water with strong flow. Maintain temperature between 23 and 27 °C (73 to 81 °F), pH at 8.1 to 8.4, and specific gravity at 1.020 to 1.025. Regular water changes and a high-performing protein skimmer are essential.
Compatibility and Cohabitation: Excellent for reef aquariums as it is reef-safe and does not harm corals or clams. It should be kept singly per tank. Introduce it as one of the last fish to the aquarium to prevent it from establishing dominant territories over newcomers.
Aquarium Breeding: Breeding has not been successfully achieved in home aquariums due to their pelagic spawning behavior. Eggs are scattered into the water column and drift in ocean currents, making larval rearing impossible in standard home setups.
Risks and Diseases: Highly prone to marine ich (Cryptocaryon) and velvet if stressed. They are also susceptible to Head and Lateral Line Erosion (HLLE) if they suffer from dietary deficiencies. A quarantine period and vitamin-enriched foods are highly recommended.
Geographic Origin and Distribution
Zebrasoma scopas, the brown tang or twotone tang, is widely distributed across the tropical Indo-Pacific, from the Red Sea and East Africa to the Tuamotu Islands, and north to southern Japan and south to the Great Barrier Reef. It inhabits coral-rich lagoons and seaward reefs at depths ranging from 1 to 60 meters, foraging on rocky substrates.
Origin
Tropical oceans and reefsAfrica and MadagascarEast Asia
Fish profile
- Temperament
- Semi-aggressive
- The Scopas Tang is considered semi-aggressive, particularly within the confines of an aquarium. While it generally ignores invertebrates and unrelated fish, it fiercely defends its grazing territory from perceived competitors. Its sharp caudal spines (scalpels) are effective weapons used during disputes. Providing a sufficiently large tank minimizes aggressive tendencies and promotes a harmonious community.
- Diet
- Herbivore
- The Scopas Tang is primarily herbivorous, needing a substantial amount of marine algae in its daily diet. It should be offered dried seaweed (nori) attached to a grazing clip to mimic natural feeding behaviors. While it enthusiastically accepts meaty foods like mysis or brine shrimp, lacking sufficient greens can lead to Head and Lateral Line Erosion (HLLE). Spirulina-enriched flakes or pellets can also supplement its nutritional requirements.
- Life expectancy
- 10-15 years
- In the aquarium, the Brown Tang has a lifespan ranging from 10 to 15 years when kept under appropriate conditions and fed a balanced diet. Some particularly hardy specimens can exceed this range in very large, mature aquariums. To promote its longevity, it is crucial to maintain stable water parameters and avoid temperature fluctuations.
- Adult size
- 20 cm
- The catalog's scalar value is 20 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 40 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Zebrasoma scopas (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Solitary
- There is no easily distinguishable sexual dimorphism in the Scopas Tang. Both males and females share the same striking coloration and identical morphological features. In a home aquarium, maintaining a specific sex ratio is generally irrelevant since keeping multiple individuals is highly discouraged. For breeding facilities, genetic testing or behavioral observation is required to confirm the sexes.
- Feeding frequency
- Twice daily
- Because of its highly active nature, this species requires multiple feedings throughout the day. Offering small meals 2 to 3 times daily ensures its high metabolic demands are met. A constant supply of grazing material, such as live macroalgae or dried nori, should be available between structured meals. Underfeeding can rapidly lead to weight loss and a weakened immune system.
- Bioload
- The Scopas Tang (Zebrasoma scopas) has a moderately high bioload typical of active surgeonfishes. It constantly grazes on algae and requires frequent feedings, which translates to a steady production of waste. A robust filtration system, including a high-capacity protein skimmer, is necessary to manage its biological impact. Regular water changes are also critical to ensure nutrient levels remain within safe parameters.
- Flow
- Strong
- Coming from turbulent reef environments, the Scopas Tang thrives in high flow aquarium setups. Strong water movement provides essential oxygenation and replicates the natural currents it encounters in the wild. Multiple powerheads or wavemakers should be positioned to create chaotic, multidirectional flow. This dynamic environment also encourages natural swimming and grazing behaviors across the rockwork.
- Jump risk
- No
- Reproduction
- Oviparous
- In the wild, Zebrasoma scopas are pelagic spawners, releasing eggs and sperm into the water column during synchronized events. They form large breeding aggregations, usually coordinating with lunar cycles and outgoing tides. Captive breeding of this tang is extremely rare and difficult due to the complex requirements of raising their microscopic larvae. Most individuals available in the hobby are wild-caught from specific locales.
- Compatibility & tankmates
- Peaceful
- This tang is generally peaceful toward most non-conspecific tank mates in a reef setting. However, it can become highly territorial and aggressive toward other surgeonfishes, especially those of the same genus or similar body shape. It is best kept as the solitary tang or introduced simultaneously with other tangs into a very large aquarium. Careful observation is required during the initial introduction to mitigate severe aggression.
- Tank level
- All levels
- This species is an active swimmer that utilizes all levels of the water column. It will constantly patrol the open water seeking food and establishing its territory. When resting or feeling threatened, it retreats to the middle and lower levels, seeking refuge within the rockwork. Ample swimming space combined with accessible hiding spots is essential for its well-being.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 2 ± 0 se
- Resilience
- Very Low (more than 14 years)
- Phylogenetic uniqueness (PD50)
- 0.5078
- Bayesian Length-Weight
- a = 0.02455, b = 2.98
- VulnerabilityModerate vulnerability (39 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
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