The Barred Rabbitfish (Siganus doliatus), also known as the Blue-Lined Rabbitfish or Scribbled Rabbitfish, is a vibrant marine species native to the Western Pacific Ocean. Renowned for its striking appearance and peaceful demeanor, this species is 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 large polyp stony corals if underfed)
• Minimum tank size: 380 litres (100 gallons)
• Adult size: Up to 25 cm (10 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 Barred Rabbitfish is easily recognisable by its distinctive colouration:
• Body: Yellowish with intricate blue lines resembling a circuit board pattern.
• Head: Features two black diagonal bars; one running through the eye and another just behind the gills.
• Fins: Yellow, complementing the body’s vibrant hues.
Natural Habitat and Behaviour
In the wild, Siganus doliatus inhabits coral-rich lagoons and seaward reefs, typically at depths ranging from 2 to 15 metres. They are often found in pairs or small groups, grazing on algae and contributing to the health of coral reef ecosystems. Their peaceful nature makes them suitable for community aquariums.
Tank Requirements and Water Parameters
• Minimum Tank Size: 380 litres (100 gallons)
• Water Parameters:
• Temperature: 23°C – 26°C (73°F – 79°F)
• pH: 8.0 – 8.3
• Specific Gravity: 1.020 – 1.025
• 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, replicating natural reef environments.
Diet and Feeding
As herbivores, Barred Rabbitfish require a diet rich in plant 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 a few 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 Barred Rabbitfish (Siganus doliatus) 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.