Bicolored foxface
Siganus uspi
The Bicolored foxface displays a striking yellow-orange body with a prominent black mask and robust, elongated dorsal fin.
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About the Bicolored foxface
A Fiji native with a sharp two-tone look, the bicolored foxface is half deep brown and half yellow with a crisp line between. It spends the day grazing algae and can snap into a mottled camouflage when spooked; those tall dorsal spines are venomous, so other fish usually keep their distance.
Also known as
Quick Facts
Size
24 cm TL (9.4 inches)
Temperament
Peaceful
Difficulty
Intermediate
Min Tank Size
125 gallons
Lifespan
8-12 years
Origin
Western Pacific - Fiji
Diet
Herbivore - marine algae, nori/seaweed sheets, spirulina; accepts pellets and frozen foods
Water Parameters
22-26°C
8.1-8.4
Need a heater for this species?
This species needs 22-26°C in a 125 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- This Fiji native tops out around 9 inches (24 cm), so give it at least a 125-gallon tank with long swimming runs and plenty of live rock to pick at and duck into.
- Hold temp at 22-26 C and pH 8.1-8.4; stable, clean water helps them reach their typical 8-12 year lifespan.
- Feed like a true herbivore: daily nori/seaweed sheets, spirulina-based foods, and marine algae, with quality pellets or frozen foods as supplements; offer multiple small feedings.
- Expect all-day grazing; when startled it can flip to a mottled camo pattern, which is normal.
- Those tall dorsal spines are venomous, so guide it with a container instead of a net and keep hands clear during maintenance.
- Generally a peaceful community fish; in coral tanks, some individuals may nip fleshy corals or prized macroalgae, especially if underfed, so watch its behavior.
- Do not rely on it as your only algae control; treat it as a helper while you manage nutrients and husbandry.
Compatibility
Good Tankmates
- Peaceful to moderately assertive tangs/surgeonfish (kole, tomini, yellow, naso) in 125+ gallons
- Reef-safe wrasses that are not bullies (fairy, flasher, calmer Halichoeres)
- Clownfish pairs, chromis, cardinalfish, and anthias
- Gobies and blennies that keep to the sand and rockwork
- Dwarf angels and Genicanthus angels; peaceful butterflyfish
- Hawkfish and other medium, non-nippy perchers
Avoid
- Triggers and nippy puffers that bite fins or spines
- Very aggressive tangs like sohal or clown tangs that patrol and chase
- Other rabbitfish or conspecifics unless a bonded pair and very large tank
- Hyper-territorial damsels, combative dottybacks, or chronic fin-nippers like sixline wrasses
Bicolored foxface (Siganus uspi)
A Fiji native with a sharp two-tone look, the bicolored foxface is half deep brown and half yellow with a crisp line between. It spends the day methodically grazing algae and can snap into a mottled camouflage pattern when spooked. This is a large, peaceful rabbitfish that reaches about 24 cm (9.4 in) and needs room to cruise.
Venomous spines: The tall dorsal spines can deliver a painful sting. Move the fish with a container rather than a net, and keep hands clear. If stung, immerse the area in hot (not scalding) water and seek medical attention.
Origin and natural habitat
Endemic to Fiji in the western Pacific, Siganus uspi lives on coral reefs where it grazes marine algae. Like other rabbitfish, it is diurnal and relies on both its camouflage and venomous spines for defense.
Aquarium setup and water conditions
This is a roaming grazer that needs space and stable, reef-like water. Provide open swimming room alongside rockwork with plenty of natural surfaces for film and turf algae.
- Minimum tank size: 125 US gallons
- Temperature: 22-26 C
- pH: 8.1-8.4
- Aquascape: sturdy rockwork with caves and overhangs, plus open areas for cruising
- Maturity: best added to a well-established tank with available algae to pick at
Allow some algae to grow on side rocks or a scrub pad you can clip in. It gives the fish something to graze between meals and reduces the urge to sample corals.
Diet and feeding
Herbivore. Offer marine algae daily and keep portions generous for this big, active fish. While it will accept prepared foods, the foundation should be seaweed and plant-based fare.
- Primary: nori/seaweed sheets, macroalgae, spirulina-based foods
- Also accepts: quality pellets and appropriate frozen items
- Feeding rhythm: multiple small feedings or a continuously available seaweed clip
- Variety helps long-term health and color
Behavior and tankmates
Generally peaceful and focused on grazing. Other fish usually give it space because of the spines. It may show a mottled stress pattern at night or when startled.
- Community: works with most peaceful and semi-aggressive reef fish that will not bully it
- With rabbitfish: best kept singly; individuals may squabble with close relatives in confined spaces
- Reef tanks: often kept in reefs, but consider it "with caution" as some individuals may nip fleshy corals or clam mantles, especially if underfed
Common issues and how to avoid them
- Underfeeding leads to coral nipping: Keep seaweed available and feed varied herbivore foods.
- Stress from cramped quarters: Provide the full 125+ gallons and clear swimming lanes.
- Handling injuries: Use a specimen container, not a net, to avoid entangling the dorsal spines.
- Shyness on arrival: Give it secure caves and keep traffic low for the first week; steady grazing and color returning are good signs of settling.
With space, stable water, and a strong plant-based diet, the bicolored foxface is a steady, long-lived grazer that can reach 8-12 years in the aquarium.
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