The Blotched Foxface (Siganus unimaculatus), also known as the One Spot Foxface, is a vibrant marine fish belonging to the rabbitfish family (Siganidae). This species is native to the central Indo-Pacific region, inhabiting coral reefs and lagoons. It closely resembles the Foxface Rabbitfish (Siganus vulpinus), differing primarily by the presence of a distinctive black spot on its upper rear body.
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: 265 litres (70 gallons)
• Adult size: Up to 24 cm (9.5 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 Blotched Foxface exhibits a striking colour pattern:
• Body: Bright yellow with a prominent black spot on the upper rear flank.
• Head: White anterior with two black bands; one running from the mouth through the eye to the start of the dorsal fin, and another from the shoulder to the chest.
• Fins: Yellow, complementing the body’s vibrant hues.
Natural Habitat and Behaviour
In the wild, Siganus unimaculatus is found in coral-rich areas of lagoons and outer reefs, often among staghorn corals. Juveniles form schools of up to several hundred individuals, while adults typically occur in pairs. They feed on seaweeds, playing a crucial role in controlling algal growth on reefs.
Tank Requirements and Water Parameters
• Minimum Tank Size: 265 litres (70 gallons)
• Water Parameters:
• Temperature: 24°C – 28°C (75°F – 82°F)
• pH: 8.1 – 8.4
• 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, Blotched Foxfaces 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 Blotched Foxface (Siganus unimaculatus) 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.