Description
Gem Tang – Zebrasoma gemmatum
Zebrasoma gemmatum, known as the Gem Tang or Spotted Tang, is one of the most spectacular and prestigious surgeonfish in the marine world. Endemic to the Western Indian Ocean, it is instantly recognizable by its deep jet-black body adorned with countless iridescent white to blue “gemstone” spots, and a glowing yellow caudal fin. Graceful, hardy, and commanding in presence, this species has long been regarded as a hallmark of elite reef aquariums.
Origin: Western Indian Ocean – Mauritius, Réunion, Madagascar, and occasionally South Africa
Depth: 10–60 m (30–200 ft)
Lighting: Moderate to high (enhances spot contrast and sheen)
Flow: Strong, laminar flow preferred; replicates reef slope surge conditions
Tank Placement: Open water column with abundant live rock for grazing
Temperature: 74–80°F (23–27°C)
Salinity: 1.022–1.026 SG
pH: 8.1–8.4
Diet: Herbivorous – feeds primarily on filamentous algae; diet should include nori, spirulina, marine vegetable blends, and enriched greens
Temperament: Semi-aggressive; territorial toward other tangs, particularly Zebrasoma species
Size: Up to 22 cm (8.5 inches)
Care Level: Advanced – requires pristine water quality, abundant swimming space, and frequent feeding to maintain vigor and coloration
Compatibility: Best kept singly in large aquariums (minimum 600 L / 160 gal); compatible with most non-aggressive reef fish
Collector’s Note: Zebrasoma gemmatum is among the most prized tangs in the global aquarium trade, collected primarily around Mauritius and Réunion in limited numbers. Its scarcity, mesmerizing beauty, and near-mythical status among aquarists earn it a permanent place in Collector’s Corner — a living masterpiece symbolizing rarity, prestige, and the art of advanced marine keeping.
