The Masked Rabbitfish (Siganus puellus), also known as the Decorated Rabbitfish or Masked Spinefoot, is a vibrant marine species native to the Indo-West Pacific region. Its distinctive appearance and herbivorous diet make it a popular choice among marine aquarists.
Key Information
• Small fish safe: ✅ Yes (generally peaceful)
• Small invertebrate safe: ✅ Yes (primarily herbivorous)
• Coral safe: ⚠️ With caution (may nip at soft and LPS corals if underfed)
• Minimum tank size: 680 litres (180 gallons)
• Adult size: Up to 38 cm (15 inches)
• Diet: Herbivorous, feeding on various algae
• Be aware of: Venomous dorsal and anal spines; handle with care to avoid envenomation
Appearance and Colouration
The Masked Rabbitfish is easily recognisable by its striking colouration:
• Body: Bright yellow adorned with intricate blue lines and spots.
• Head: Features a prominent black diagonal stripe running from the mouth through the eye, resembling a mask.
• Fins: Yellow, complementing the body’s vibrant hues.
Natural Habitat and Behaviour
In the wild, Siganus puellus inhabits coral-rich areas of lagoons and seaward reefs, often found at depths ranging from 1 to 30 metres. Juveniles typically form large schools in sunny lagoon areas dominated by Acropora coral species, while adults are commonly seen in pairs.
• Diet: Primarily feeds on benthic algae, playing a crucial role in controlling algal growth on reefs.
Tank Requirements and Water Parameters
• Minimum Tank Size: 680 litres (180 gallons)
• Water Parameters:
• Temperature: 22°C – 27°C (72°F – 82°F)
• pH: 8.0 – 8.5
• Specific Gravity: 1.020 – 1.026
• Aquascaping: Provide ample live rock for grazing and hiding spots, along with open swimming areas.
• Lighting: Moderate to high, supporting algal growth for natural grazing.
• Water Movement: Moderate to strong, replicating natural reef environments.
Diet and Feeding
As herbivores, Masked Rabbitfish require a diet rich in vegetable matter:
• Primary Diet:
• Marine algae or algae sheets (e.g., nori)
• Blanched greens such as lettuce or spinach
• High-quality marine herbivore pellets or flakes
• Supplementary Foods:
• Occasional offerings of mysis or brine shrimp
• Feeding Frequency: Provide algae or algae sheets continuously for grazing; offer other foods 2–3 times daily, ensuring only what they can consume in 1–2 minutes to prevent overfeeding.
Compatibility and Social Structure
• Temperament: Generally peaceful; may become territorial towards other rabbitfish species.
• Tank Mates: Compatible with a variety of peaceful to moderately aggressive species; caution advised when housing with other rabbitfish to prevent aggression.
Important Considerations
• Venomous Spines: Possess venomous dorsal and anal fin spines capable of inflicting painful wounds; exercise caution during tank maintenance and handling.
• Reef Compatibility: While generally reef-safe, underfed individuals may nip at certain soft and large polyp stony (LPS) corals; ensure adequate feeding to mitigate this risk.
• Dietary Needs: A diet rich in vegetable matter is essential; insufficient feeding may lead to undesirable behaviours, including coral nipping.
Summary
The Masked Rabbitfish (Siganus puellus) is a vibrant and beneficial addition to large marine aquariums, particularly valued for its algae-grazing habits. Aquarists must exercise caution due to its venomous spines and ensure a diet rich in vegetable matter to maintain health and appropriate behaviour. With proper care, this species can thrive and contribute positively to the aquarium ecosystem.