Barhead Spinefoot (Siganus virgatus)
The Barhead Spinefoot (Siganus virgatus), also known as the Two-Barred Rabbitfish, is a striking and adaptable species found in the Indo-West Pacific. Recognised for its algae-grazing habits and peaceful nature, it is a valuable addition to large marine aquariums. However, like all rabbitfish, it possesses venomous spines, requiring careful handling.
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 450 litres (120 gallons)
• Adult size Up to 30 cm (12 inches)
• Diet Herbivorous, feeding on various algae
• Be aware of Venomous dorsal, anal, and pelvic fin spines; handle with caution
Appearance and Colouration
The Barhead Spinefoot is easily recognisable due to its distinctive colouration and patterning:
• Body Colouration
The body is pearlescent white, fading into bright yellow along the dorsal area and tail.
• Head Markings
Two bold black bands, one running through the eye and another behind the gills, give the species its name.
• Camouflage Ability
It can darken or pale in colour depending on mood and environment.
Natural Habitat and Behaviour
In the wild, Siganus virgatus is found in coral reef lagoons and coastal reef slopes, often in pairs or small groups. This species is diurnal, spending its days grazing on algae and retreating to shelter at night.
• Habitat
Found at depths of 2 to 25 metres, typically near coral rubble zones and seagrass beds.
• Algae Control
Plays an essential role in controlling nuisance algae in reef environments.
Tank Requirements and Water Parameters
• Minimum Tank Size 450 litres (120 gallons)
• Water Parameters
• Temperature 22°C – 26°C (72°F – 78°F)
• pH 8.1 – 8.4
• Specific Gravity 1.020 – 1.025
• Aquascaping
• Provide ample live rock for grazing and shelter.
• Allow open swimming space to accommodate their active nature.
• Lighting Moderate to high to encourage algal growth for grazing.
• Water Movement Moderate, mimicking reef conditions.
Diet and Feeding
As herbivores, Barhead Spinefoots require a plant-based diet to remain healthy and reduce the risk of coral nipping.
• Primary Diet
• Marine macroalgae and algae sheets (e.g., nori).
• Blanched spinach, romaine lettuce, and seaweed.
• High-quality herbivore pellets and flakes.
• Supplementary Foods
• Occasional mysis shrimp or brine shrimp.
• Feeding Frequency
2–3 times per day, ensuring continuous access to algae for grazing.
Compatibility and Social Structure
• Temperament
• Peaceful, making it suitable for community aquariums.
• May become territorial with other rabbitfish species.
• Suitable Tank Mates
• Compatible with tangs, angelfish, clownfish, and wrasses.
• Avoid housing with aggressive species that may bully or stress it.
Important Considerations
• Venomous Spines
• The dorsal, anal, and pelvic spines contain venom that can cause painful stings.
• Always be aware of their location during tank maintenance.
• Reef Compatibility
• Mostly reef-safe, but may nip at corals if underfed.
• Algae Control Role
• Helps maintain low algae levels in large aquariums.
Summary
The Barhead Spinefoot (Siganus virgatus) is a hardy, algae-grazing species that thrives in large, well-maintained marine aquariums. With proper diet and stable water conditions, it serves as both a beautiful and functionaladdition, helping to prevent algae overgrowth. However, its venomous spines and potential for coral nipping require careful management.