One Spot Foxface

The One Spot Foxface (Siganus unimaculatus) is a striking rabbitfish recognized by its brilliant yellow body, contrasting white and black facial markings, elongated fox-like snout, and distinctive dark spot on the upper rear portion of the body. Closely resembling the Foxface Lo, this identifying black blotch gives the species its familiar common name and adds another bold visual element to an already colorful saltwater fish.

Native to the Western Pacific, including the Ryukyu Islands, Philippines, and waters extending toward northwestern Australia, the One Spot Foxface inhabits coral-rich lagoons and outer reef environments. In nature, it spends much of its time grazing on seaweed and algae while moving between reef structures for shelter.

Generally peaceful toward unrelated tankmates, this active marine aquarium fish is especially desirable for established reef aquariums because of its algae-grazing behavior. It can also thrive in fish-only aquariums with appropriate space and nutrition. Like other rabbitfish, however, it possesses venomous fin spines and should be handled with care.

Quick Care Guide

Care Level: Easy
Minimum Tank Size: 100 gallons
Temperament: Peaceful
Diet: Herbivore
Reef Safe: With Caution
Region: Western Pacific
Scientific Name: Siganus unimaculatus

Tank Requirements

Provide a spacious aquarium with plenty of open swimming room along with established rockwork for grazing and shelter. Caves, overhangs, and protected areas within the aquascape give the One Spot Foxface places to retreat when frightened and during nighttime resting.

Because this species is an active swimmer and reaches approximately 8 inches in adult standard length, adequate horizontal swimming space is important for long-term housing. Mature live rock is particularly beneficial because it provides natural algae and additional grazing opportunities throughout the day.

Moderate to strong water movement, efficient filtration, and stable water quality are recommended. A secure aquarium cover is also beneficial, especially while a newly introduced specimen is adjusting to its surroundings.

Diet and Feeding

The One Spot Foxface is primarily herbivorous and should receive a diet rich in marine algae and vegetable matter. Dried seaweed or nori should be offered regularly, ideally on a feeding clip where the fish can graze naturally.

Supplement algae with spirulina-based foods, high-quality herbivore pellets, and frozen preparations formulated for marine grazers. Mysis shrimp, enriched brine shrimp, and other mixed frozen marine foods can be offered occasionally for additional nutritional variety.

Feed one to three times daily depending on the amount of natural algae available in the aquarium. Consistent access to appropriate plant-based foods helps maintain body condition and may reduce unwanted grazing on coral tissue.

Temperament and Tankmates

The One Spot Foxface is generally peaceful with unrelated marine fish and is well suited to community aquariums containing similarly sized species. Appropriate tankmates can include tangs, angelfish, clownfish, wrasses, anthias, gobies, and other peaceful to moderately assertive marine fish.

Territorial behavior is more likely toward other rabbitfish and especially similarly shaped Foxface species. A single specimen is generally recommended unless the aquarium is exceptionally large or a compatible pair is being maintained.

When frightened, stressed, or sleeping, the fish can rapidly develop darker or mottled coloration. This temporary color change is normal for rabbitfish and typically disappears once the fish becomes active and comfortable again.

Its dorsal, anal, and pelvic spines are venomous and serve primarily as a defensive mechanism. The fish does not normally attack with these spines, but care should be taken when working around it or transferring it between containers.

Reef Compatibility

Reef Safe: With Caution.

The One Spot Foxface is commonly maintained in reef aquariums and is especially valued for grazing on algae growing across rockwork. It generally ignores ornamental shrimp, crabs, snails, and other mobile invertebrates.

Coral compatibility can vary between individual fish. Some specimens may nip at fleshy LPS corals, zoanthids, soft corals, or other sessile organisms, particularly if adequate algae and supplemental food are not available. Keeping the fish well fed reduces the likelihood of unwanted grazing but cannot guarantee complete coral safety.

Water Parameters

Temperature: 75–80°F
Specific Gravity: 1.024–1.026
pH: 8.1–8.4
Alkalinity: 8–12 dKH

Stable water conditions are more important than maintaining one exact value within these ranges. Avoid rapid changes in temperature, salinity, or pH, particularly during acclimation.

Common Considerations

• Possesses venomous dorsal, anal, and pelvic spines and should be handled carefully.

• Requires regular access to marine algae and a vegetable-rich diet.

• May become territorial toward other Foxface and rabbitfish species.

• Can temporarily darken or develop mottled coloration when frightened, stressed, or sleeping.

• Generally adapts well to reef aquariums but may occasionally nip at soft corals, zoanthids, or fleshy coral tissue.