Also Known As: Fiji Foxface, Uspi Rabbitfish

Compatibility and Behavior
The Bicolor Foxface (Siganus uspi) is the most graphically marked member of its family. Roughly the front two-thirds of the body is a deep purplish-brown to near-black that transitions along a crisp, almost ruler-straight line into brilliant lemon yellow across the rear third, tail, pectoral fins, and the soft portions of the dorsal and anal fins, with a broad whitish diagonal band across the chin. Endemic to Fiji, it's seen far less often in the trade than the common Foxface Lo, and that block coloration makes it instantly identifiable.
Note on stress coloration: like other rabbitfish, it can switch off that pattern in seconds, replacing it with drab mottled camouflage when sleeping or startled while erecting its dorsal spines, so a suddenly blotchy fish is usually just resting or nervous rather than sick, and the color returns as it settles. These are tireless, graceful grazers that cruise the full height of the tank picking algae much like a tang, and many reefers add them specifically for that appetite, which extends to hair algae, filamentous algae, and even nuisance bubble algae. Reef compatibility comes with the standard rabbitfish caveat: a well-fed specimen is generally trustworthy, but an underfed one may nip, so steady greens are the real safeguard. Fish compatibility is genuinely easy, since their venomous spines mean even triggers, groupers, and large angels tend to leave them alone, while their peaceful nature means they won't bully gobies, anthias, cardinalfish, or mandarins. Handling requires real caution, as the 13 dorsal spines plus the anal and pelvic spines carry venom and can deliver a painful sting, so wear gloves, know where the fish is before reaching in, and soak any sting in hot water while seeking medical attention.

Aquarium Requirements
This is an active, wide-ranging swimmer that reaches a substantial adult size, and the sturdy Lg to XL specimens we carry need a permanent home of 125 gallons or larger with at least 18 inches of width and ideally a six-foot footprint. Undersized tanks are a real problem for this species specifically, since confined foxfaces tend to pace the same circuit all day rather than graze naturally. Build around long, open swimming lanes fronting plenty of mature live rock, which doubles as grazing pasture and as crevices to wedge into overnight. A sand substrate suits it, moderate flow with good surface agitation reflects the coral-rich lagoons and reef slopes it comes from, and moderate to strong lighting encourages the algae film it feeds on. Adding one to a well-established tank with existing algae makes it feel right at home. Supplement grazing with dried nori or Ulva on a clip at least three times a week along with spirulina flakes, herbivore pellets, and vegetable-based frozen preparations, offering meaty items only in moderation. A tight-fitting lid is recommended, and a rigid specimen container is far safer than a mesh net for moves.

Specifications
Approximate Size: Md: 2–3.5", Lg: 3.5–4.5", XL: 4.5–6"
Diet: Herbivore; dried nori and Ulva on a clip, spirulina flakes, herbivore pellets, and vegetable-based frozen foods, supplemented by natural algae grazing on live rock, with occasional mysis or spirulina brine, fed 2–3 times daily
Origin: Endemic to Fiji
Care Level: Easy to moderate
Reef Safe: With caution
Temperament: Peaceful
Special Considerations: Venomous dorsal, anal, and pelvic spines can deliver a painful sting, so wear gloves and move it in a rigid container rather than a net. Reef safe with caution, as an underfed fish may nip corals, so keep it well grazed on greens.