Yellow Foxface Rabbitfish

Yellow Foxface Rabbitfish: The Algae Grazer with Venomous Spines

The Yellow Foxface Rabbitfish (Siganus vulpinus), commonly referred to simply as the Foxface Lo or Foxface Rabbitfish, is a strikingly beautiful and highly beneficial marine fish. Recognizable by its elongated, fox-like snout and electric yellow body, it features a distinctive pattern of black and white markings covering its face and chest. The face marking often makes it look like it's wearing a black mask.

Native to the coral-rich lagoons and seaward reefs of the Western Pacific (from Indonesia to the Great Barrier Reef), the Foxface is a popular choice for reef and FOWLR aquariums due to its peaceful temperament and prolific appetite for nuisance algae. This species is an active swimmer, growing to a maximum size of around 8 to 9 inches (20-23 cm). A minimum tank size of 100 to 125 gallons is recommended to provide ample swimming room and grazing territory.

A notable feature of all Rabbitfish is the presence of 13 sharp, venomous dorsal spines (and spines on the anal and pelvic fins). While they are peaceful and use these spines only defensively, the sting is highly painful. Extreme caution must be exercised during handling or tank maintenance.

Diet & Compatibility:

• Diet: The Foxface is primarily a Herbivore and a dedicated algae grazer. Its diet must be rich in plant matter to remain healthy and prevent head and lateral line erosion (HLLE). Provide plenty of quality marine algae, such as Nori sheets clipped to the tank glass, spirulina flakes, and herbivore pellets. Although it will accept meaty foods like mysis or brine shrimp, these should only be offered as an occasional supplement.
• Algae Control: This species is highly valued for its ability to consume certain types of nuisance algae, including hair algae and even some Bryopsis strains.
• Reef Compatibility: It is considered Reef Safe With Caution. While the Foxface generally ignores small fish and invertebrates, if underfed, it may begin to nip at the fleshy polyps of certain LPS (Large Polyp Stony) or soft corals like Xenia or Montipora. Keeping it well-fed on greens is the best way to mitigate this risk.
• Temperament: Peaceful with most tankmates, even semi-aggressive fish like Triggerfish or Groupers, as its venomous spines deter potential predators. It is generally intolerant of other Rabbitfish (conspecifics) and should be kept singly or as a bonded pair, requiring close monitoring if another Rabbitfish is introduced.
• Stress Behavior: When stressed or sleeping, the Foxface will rapidly change its coloration to a dark, mottled pattern of browns and blacks for camouflage. This is a natural response and not a sign of illness.
• Venomous Spines: If stung, immediately immerse the affected area in the hottest water you can tolerate (not scalding) for 30-90 minutes, as heat breaks down the protein-based venom. Seek medical attention immediately.

Quick Facts

• Scientific Name: Siganus vulpinus
• Primary Common Name: Yellow Foxface Rabbitfish
• Other Common Names: Foxface Lo, Foxface, Common Foxface
• Origin: Western Pacific (Indo-Pacific, Great Barrier Reef)
• Max Size: 8-9 inches (20-23 cm)
• Temperament: Peaceful (Venomous Spines)
• Diet: Herbivore (Primarily algae/Nori)
• Minimum Tank Size: 100-125 Gallons
• Reef Compatibility: With Caution (May nip corals if underfed)