Foxface Rabbitfish
Siganus vulpinus
The Foxface Rabbitfish features a yellow body with distinctive black markings and long dorsal spines that resemble a fox's face.
This page includes AI-generated images. Why am I seeing AI images?
About the Foxface Rabbitfish
Siganus vulpinus is that bright yellow "fox-masked" rabbitfish you see cruising around picking at algae all day. It's generally chill with other fish, but it can get a little bossy with similar-shaped grazers-and those dorsal spines are venomous, so nets and hands need to be treated with respect.
Also known as
Quick Facts
Size
25 cm (about 9.8 inches)
Temperament
Semi-aggressive
Difficulty
Intermediate
Min Tank Size
125 gallons
Lifespan
8-12 years
Origin
Western Pacific (Indo-Pacific)
Diet
Herbivore/omnivore grazer - mainly algae/nori/spirulina foods, plus occasional meaty frozen foods
Water Parameters
23.8-31.2°C
8-8.4
8-12 dGH
Need a heater for this species?
This species needs 23.8-31.2°C in a 125 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Give a foxface room to cruise-think 90g+ with lots of open swim space and a few rock caves to duck into when it gets spooked.
- Keep salinity steady around 1.025 and temp 75-79°F; they're hardy, but they sulk (and get spotty) when salinity swings or nitrates stay high.
- Feed like a herbivore that still likes snacks: nori on a clip most days, plus spirulina/marine algae foods; toss in mysis or brine occasionally but don't make it the main diet.
- They're great for nuisance algae, but they can also "taste test" some softies/LPS if they're hungry-keep them well-fed if you want your corals left alone.
- Tankmates: generally chill with other peaceful fish; avoid housing with super aggressive tangs/triggers that will harass it, and don't mix with other rabbitfish in smaller tanks unless it's a big system.
- Watch the dorsal spines-venomous and painful; use a container instead of a net when moving it, and don't corner it with your hand in the rockwork.
- If it suddenly turns blotchy/dark, that's usually stress camo (lights off, new tankmates, being chased); give it hiding spots and reduce bullying before you start dumping meds.
Compatibility
Good Tankmates
- Peaceful clownfish (Ocellaris/Percula) - they mostly mind their own business and the foxface just cruises around grazing.
- Fairy or flasher wrasses - active but not usually pushy, and they won't compete much with the foxface's 'constant grazer' vibe.
- Tangs that aren't total jerks (Kole/Yellow/Eye-bristle types in a big tank) - usually fine if there's room and plenty of nori/algae so nobody gets possessive.
- Peaceful gobies and blennies (watchman goby, tailspot blenny, etc.) - they stick to their zones and the foxface ignores them.
- Reef-safe-ish community fish like chromis or cardinals - good 'middle water' fish that don't mess with a foxface.
- Most dwarf angels (coral beauty/flame) in a roomy setup - usually works; just keep everyone well-fed so it doesn't turn into 'who owns the rockwork'.
Avoid
- Other rabbitfish/foxfaces - mixing is asking for turf wars unless the tank is huge and you add them together; otherwise they'll often scrap.
- Aggressive/nippy triggers (clown/picasso, etc.) - they'll pester the foxface and that stress tends to bring out the foxface's defensive spine drama.
- Pushy big wrasses and similar bullies (harlequin tusk, large Thalassoma types) - they can harass a foxface nonstop, especially at feeding time.
- Territorial dottybacks (especially in smaller tanks) - they love picking fights and can keep a foxface on edge around caves and rockwork.
1) Where they come from
Foxface rabbitfish (Siganus vulpinus) come from Indo-Pacific reefs and lagoons—places with bright light, lots of rock, and endless grazing opportunities. That “horse face” snout isn’t just cute; it’s made for picking algae and bits of planty stuff out of cracks all day.
2) Setting up their tank
Think “room to cruise + rock to graze.” A foxface is active and gets chunky fast. You can start one in a 75g if it’s a smaller fish, but long-term I’ve had the best luck (and least pacing) in 90g+ with open swimming lanes.
- Tank size: 75g minimum for a smaller one; 90–125g feels more natural as they grow
- Aquascape: rockwork with lots of surfaces for algae, plus open areas up front
- Flow/oxygen: moderate flow and good gas exchange—they’re constant movers
- Cover: they can spook and bolt; a lid or mesh top saves lives
- Hiding spot: one “cave” or overhang they can wedge into at night
If your foxface turns mottled or looks like it’s wearing camouflage at night, that’s normal. Mine always did the “pajamas” look when sleeping or stressed, then went bright yellow again after lights-on.
They have venomous dorsal spines. Not aggressive, but you don’t want to get tagged while netting or moving rock. Use a container to catch them when you can, and go slow.
3) What to feed them
They’re hungry herbivores/omnivores with a strong bias toward greens. If you feed only meaty frozen, they’ll survive… but you’ll be fighting a losing battle with weight, digestion, and “why is it nipping my corals?” behavior.
- Nori/seaweed sheets (daily if possible) clipped to the glass or on a feeding rock
- Spirulina flakes/pellets as a staple
- Frozen mixes with some veggie content (mysis is fine, just not as the main event)
- Blanched macroalgae if you have it (some will eat it, some ignore it)
- Occasional treats: chopped clam, brine, mysis—think “snack,” not “diet”
Give them a grazing routine: a nori sheet in the morning, then a smaller feeding later. Foxfaces calm down a lot once they learn food shows up reliably.
If they’re underfed on greens, they may sample soft corals or certain LPS. It’s not guaranteed, but hunger makes it way more likely.
4) Behavior and tankmates
Foxfaces are generally peaceful, a little shy at first, and then oddly personable once they settle in. Mine would follow me from end to end like a yellow puppy. They’re not usually bullies, but they’re big enough that timid fish can get intimidated just by the constant cruising.
- Good tankmates: tangs (usually), clownfish, wrasses, cardinals, gobies, dwarf angels (case-by-case), most reef-safe community fish
- Be careful with: very aggressive triggers, big mean dottybacks, or anything that likes to harass newcomers
- Other rabbitfish: possible in large tanks, but don’t assume it’ll be peaceful—introductions matter
- Inverts: typically fine with shrimp/snails; they’re not known invert hunters
They’ve got a neat defense trick: they can “lock” their dorsal spines. If a tankmate tries to take a bite, it gets a mouthful of bad decisions. That’s why they usually don’t need to be aggressive to hold their own.
5) Breeding tips (realistically)
Breeding foxfaces in home aquariums is pretty uncommon. In the wild they’re pelagic spawners (eggs and larvae drifting in the water column), which is a tough project without a serious larval setup. If you keep a pair and they get comfortable, you might see courtship behavior, but raising babies is a whole different hobby.
If you ever want to try, the biggest hurdles are: getting a true pair, providing a big stable system, and having live foods ready for tiny larvae (rotifers, then nauplii, etc.). Most folks focus on keeping them fat and happy instead.
6) Common problems to watch for
They’re pretty hardy once they’re eating, but the first couple weeks tell you everything. A foxface that won’t take greens or hides nonstop is usually stressed, getting bullied, or dealing with parasites.
- Marine ich/velvet: they can get hit like any other fish—watch for flashing, heavy breathing, and dusting/spots
- Refusing food: often shipping stress; offer nori first and keep the tank calm
- HLLE (head and lateral line erosion): more likely in systems with poor diet/low variety and lots of stray stress
- Coral nipping: usually a “not enough algae food” issue or a bored grazer in a too-clean tank
- Spine stings (you): not a fish health issue, but a common hobbyist problem
Don’t try to net them in a tight space unless you have to. Spines + net = stuck fish and a stressed-out mess. I use a clear specimen container and gently herd them in.
If you get stung: hot water (as hot as you can stand) helps with marine venom pain. Seek medical help if pain is severe, spreading, or you have any allergic-type symptoms. Not trying to scare you—just don’t tough it out if it’s bad.
Similar Species
Other marine semi-aggressive species you might be interested in.
Blackspotted snake eel
Quassiremus ascensionis
A tropical marine snake eel that buries in soft substrates (sand/mud/gravel) with only the head exposed to ambush prey. Recorded to 71 cm TL and occurs mainly in the western Atlantic (also Brazil) and at Ascension Island; typically found in shallow inshore habitats to ~12 m, including sand and seagrass (turtle grass) areas.
Blue blanquillo
Malacanthus latovittatus
A long, slim tilefish with a bold black side stripe and a blue head that fades down the body. It hovers high above the reef and darts back to a sand-rubble burrow, often living as a monogamous pair; in tanks it is fast, jump-prone, and will eat small crustaceans and tiny fish.
Blue Green Chromis (Green Chromis)
Chromis viridis
Blue Green Chromis are those shimmery little green-blue darts you'll see zipping around the top of a reef tank, always looking like they're catching the light just right. They're super fun in a group because they hover and cruise together, but they've got a bit of a "pecking order" thing going on if the tank's tight or the group's too small.
Blueline demoiselle
Chrysiptera caeruleolineata
A little reef damsel with a bright electric-blue line riding over a yellow body, it tends to live deeper on rubble slopes and hugs the bottom in small groups. In aquariums it prefers dimmer light, plenty of rock cover, and frequent small feedings of planktony foods; males guard eggs stuck to the substrate.
Bluespotted angelfish
Chaetodontoplus caeruleopunctatus
A medium Pomacanthid from the Philippines, it has a dusky body dusted with tiny electric-blue spots and a yellow tail. In the wild it browses sponges and tunicates on deeper reefs, so it thrives only in mature tanks with lots of live rock and frequent feedings.
Broadbarred firefish
Pterois antennata
This is the lionfish with the long "antennae" (those banded tentacles above the eyes) and the ragged, spotty fins that make it look extra dramatic under reef lighting. It'll spend the day tucked under ledges and then cruise out at dusk to ambush shrimp, crabs, and any small fish it can fit in its mouth-also worth remembering it's venomous, so you treat it with respect when you're in the tank.
More to Explore
Discover more marine species.
Banggai Cardinalfish
Pterapogon kauderni
Banggai cardinals just sort of hover like little underwater satellites, and the bold black bars with those long, polka-dotted fins look unreal under reef lighting. They're super chill most of the time, but once a pair forms you'll see real "fish drama," and the male will even mouthbrood the babies like a champ.
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 grazing algae and can snap into a mottled camouflage when spooked; those tall dorsal spines are venomous, so other fish usually keep their distance.
Blackfin slatey
Diagramma melanacrum
A large sweetlips from Southeast Asian reefs with a pale silvery-yellow body sprinkled in dark spots and distinct black pelvic and anal fins. Juveniles linger in silty shallows, while adults rest in small groups on deeper reef walls by day and roam at night to pick off crabs, shrimp, and other invertebrates.
Blackspot razorfish
Iniistius dea
This is one of the coolest "knife-bodied" wrasses - it hangs over open sand and, when it gets spooked or wants to sleep, it literally torpedoes straight into the sand. Give it a deep, fine sand bed and it will act totally different (and way more natural) than a typical rock-hugging reef wrasse. Adults are usually shy and cruisy with tankmates, but they are not forgiving about rough handling or sketchy setups.
Blueband goby
Valenciennea strigata
This is that classic gold/yellow-headed sand-sifting goby with the little blue cheek stripe-always busy, always rearranging your sandbed. In a reef tank it'll spend the day taking mouthfuls of sand, filtering out tiny critters/foods, then "snowing" clean sand back out, and it'll usually claim a burrow area (often as a pair in the wild). It's super cool behavior-wise, but you really do need a mature tank with a proper sandbed and a lid because they can jump.
Bluespotted dottyback
Pseudochromis persicus
A striking dark-bodied dottyback covered in tiny blue spots from the Persian Gulf and nearby western Indian Ocean reefs. It grows larger than most dottybacks and throws a lot of attitude for its size, staking out caves and defending them hard. Best for roomy marine setups with robust tankmates and plenty of rockwork to break lines of sight.
Looking for other species?