Variegated cardinalfish
Fowleria variegata
The Variegated cardinalfish features a distinctive mix of red, orange, and blue markings with elongated dorsal and anal fins.
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About the Variegated cardinalfish
This is a small, mottled reddish-brown cardinalfish that likes to hang around rockwork and rubble and really comes into its own once the lights dim. In a calm reef tank its a super chill, slow swimmer, and if you keep a small group they tend to hover together and look way more natural.
Also known as
Quick Facts
Size
8 cm
Temperament
Peaceful
Difficulty
Beginner
Min Tank Size
30 gallons
Lifespan
3-5 years
Origin
Indo-Pacific
Diet
Carnivore (planktivore) - small meaty foods like mysis, brine, copepods, and finely chopped frozen foods; will often take quality pellets/flake once settled
Water Parameters
22-28°C
8.1-8.4
8-12 dGH
Need a heater for this species?
This species needs 22-28°C in a 30 gallon tank. Use our heater calculator to find the right wattage.
Calculate heater sizeCare Notes
- Give them a bunch of hiding spots (rock caves, overhangs, or a little branching coral) and keep the lighting on the calmer side - they hang back and feel safer with cover.
- Keep salinity steady around 1.025-1.026 and temp about 76-79F; they get cranky fast if salinity swings from sloppy top-offs.
- They are small-mouthed pickers, so feed small meaty stuff: mysis, finely chopped shrimp, calanus, and good pellets that sink. Two small feedings beats one big dump because they are slow and can miss out.
- Peaceful tankmates only - think gobies, blennies, small wrasses. Skip aggressive dottybacks, big damsels, and anything that will outcompete them at feeding time.
- They usually do fine singly, but if you want a group, add several at once and give lots of caves so one fish does not claim the whole rock pile.
- Watch for them getting skinny with a full tank - that is almost always a feeding competition problem, not a mystery disease. Target feed with a pipette near their hideout if needed.
- Breeding is cool but subtle: pairs will mouthbrood, and you will see one holding eggs and refusing food for a bit. If you ever want the babies, you will need a separate rearing setup and tiny foods (rotifers/copepods) because they are not going to survive in a busy reef.
Compatibility
Good Tankmates
- Other small peaceful reef fish - think ocellaris/percula clownfish pairs (not maroons) in a normal-sized tank. Cardinals mostly mind their own business and clowns usually do too if you stay out of their anemone territory.
- Firefish (Nemateleotris spp.) and other shy dartfish. Similar vibe - calm, hover-y, and they are not looking for trouble. Just make sure you have a lid because firefish are jumpers.
- Watchman gobies and small sand-sifting gobies (Yellow watchman, Randall's, etc.). Cardinals hang midwater and the goby does its own thing on the bottom, so they basically ignore each other.
- Blennies like tailspot blenny or bicolor blenny (the more mild ones). Good personality match and they will not hassle a cardinal as long as the blenny is not a cranky territory hog.
- Flasher/fairy wrasses (the chill smaller ones). Active but usually not mean, and they do not fixate on cardinals. Great for adding movement while the cardinal does the hovering thing.
- Peaceful reef-safe inverts and corals - cleaner shrimp, peppermint shrimp, snails, softies/LPS. Variegated cardinals are planktivore-ish and tend to leave sessile stuff alone.
Avoid
- Dottybacks (especially orchid dottyback) and other 'cute but spicy' rock bullies. They can pin a cardinal into a corner and just keep at it, especially in smaller rockwork-heavy tanks.
- Hawkfish (flame hawk, longnose hawk). They are perch-and-pounce hunters and can stress small cardinals, plus they are notorious for making snack decisions about shrimp.
- Big or aggressive wrasses and 'nippy' fish - sixline wrasse (often turns into a jerk), larger Halichoeres, and anything that spends the day policing the tank. Cardinals are slow and get pushed around.
- Predators and mouthy fish - groupers, lionfish, big grammas, large angels. If it can fit a cardinal in its mouth (or try), it will eventually test that theory.
Where they come from
Variegated cardinalfish (Fowleria variegata) are Indo-Pacific reef fish you will usually find hanging around rubble zones, ledges, and branching coral. They are classic "hang in the shade and pick food out of the water" fish. In a tank, that translates to: calm lighting, places to hover, and steady small meals.
Setting up their tank
These are beginner-friendly because they are not super demanding, but they do better when you give them a peaceful, structured setup. Think caves, overhangs, and some branching rockwork where they can hover without being blasted by flow.
- Tank size: 20-30 gallons works for a single fish or a bonded pair; go bigger if you want a small group
- Aquascape: lots of nooks and shaded spots, plus a clear area for feeding
- Flow: moderate; give them at least one calmer zone so they are not constantly fighting the current
- Lighting: anything reef-normal is fine, but they appreciate shadowy areas
- Water stability: standard reef parameters and steady salinity matter more than chasing exact numbers
If your cardinalfish stays wedged in one corner all day, it is usually flow and/or not enough cover. Add an overhang or redirect a powerhead and they often relax within a day.
What to feed them
Mine have always been easy eaters once settled. They are micro-predators, so small meaty foods are the move. The only catch is they can be shy at first, especially if you have bold fish that rush the surface.
- Frozen: mysis, brine (better as a mixer than a staple), finely chopped krill, copepod blends
- Dry: small sinking pellets and granules (start by mixing with frozen so they recognize it)
- Live (great for new arrivals): live baby brine or live copepods to kickstart feeding
Feed small portions 1-2 times a day rather than one big dump. They are built for frequent little snacks, and it keeps shy fish from missing out.
How they behave and who they get along with
Variegated cardinals are peaceful and a bit "hover-y". They spend a lot of time in the midwater near structure, and they are not going to compete with pushy fish. The good news is they rarely bother anything else.
- Good tankmates: clownfish (not overly aggressive ones), gobies, blennies, firefish, small wrasses that are not bullies, peaceful tangs in larger tanks, cleaner shrimp and most other inverts
- Use caution with: dottybacks, bigger damsels, aggressive clowns, and anything that turns feeding time into a brawl
- Avoid: large predatory fish (groupers, big hawkfish, lionfish), since cardinalfish can become expensive snacks
Shy feeding is the number one "mystery problem" with these. If they look fine but slowly get thinner, watch who is stealing the food and adjust how you feed.
If you keep more than one, watch for pecking if the tank is tight or the rockwork is too open. A bonded pair is usually calm. Small groups can work in bigger tanks with lots of visual breaks, but you do not want them forced to share one little cave.
Breeding tips
Like many cardinalfish, Fowleria variegata are mouthbrooders. The male typically holds the eggs in his mouth. In a community reef, you might see the holding behavior (he stops eating and keeps his mouth slightly "full" looking), but raising the babies is the tricky part.
- If you spot a holding male: keep the tank calm and avoid big changes; stress can make him spit the clutch
- Have a plan for fry food: rotifers and/or very small live foods are usually needed at first
- A separate rearing tank helps a lot, because fry will get picked off quickly in most reefs
Do not be surprised if you never see fry in a mixed reef. Even if the pair breeds, the babies are bite-sized for almost everyone.
Common problems to watch for
- Not eating after purchase: give them cover, lower competition at feeding time, and try live foods for a few days
- Getting outcompeted: target feed with a pipette or feed on the "shy side" of the tank first
- Marine ich/velvet risk: they can look fine until they do not; quarantine new fish if you can and watch breathing and flashing
- Jumping: they are not the worst jumpers, but they can hop when spooked - a lid is cheap insurance
- Wasting away: usually a mix of stress, parasites, or simply not getting enough food; check belly shape over time, not just one day
Fast breathing, hanging in the flow, and refusing food for more than a day or two right after introduction can be a red flag for velvet or severe stress. Do not just wait it out - act early.
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