The Maroon is the largest and most aggressive clownfish, with deep maroon-red colour and white or gold stripes.
The female grows much larger than the male and dominates the pair.
It is hardy and long-lived, but its temperament makes it unsuitable for peaceful community tanks.
Note that the former genus Premnas was merged into Amphiprion in 2021, so older sources list it as Premnas biaculeatus.
With this clownfish, size and attitude matter.
A large female harasses tankmates, nips hands during maintenance, and bullies smaller fish.
Choose it for its appearance only if you can give it space and select tankmates carefully.
Housing
Provide at least 210L (55 gal) for the adult size and territorial range, with robust live rock structure.
Keep salinity 1.024-1.026, temperature 24-27°C (75-80°F), pH 8.1-8.4, and nitrate below 20 ppm in a fully cycled system.
A secure lid prevents jumping.
Introduce a true bonded pair while young, or keep a single fish, since unbonded adults fight viciously.
Add the Maroon last so it cannot claim the whole tank before tankmates settle.
Strong, stable conditions keep this large clownfish healthy long-term.
Diet
Maroons are hearty omnivores.
Feed a marine pellet staple plus meaty frozen foods such as mysis and chopped seafood, with some algae-based food for balance.
Adults have big appetites, so feed once or twice daily without overfeeding the tank.
They accept prepared foods readily, especially captive-bred specimens.
A varied diet supports their colour and immune strength.
Soak frozen foods in vitamins occasionally and do not let uneaten food foul the water.
Health
Like all clownfish they are prone to marine ich and Brooklynella when stressed, but their hardiness makes serious illness uncommon in stable water.
Quarantine new fish and keep salinity and temperature steady to avoid outbreaks.
Watch for scratching, white spots, or laboured breathing.
Their aggression can also injure tankmates, so monitor other fish for fin damage rather than the robust Maroon itself.
Good husbandry keeps them healthy for well over a decade.
Temperament
The Maroon is the most belligerent clownfish, with females in particular defending a large territory and bullying tankmates and even the aquarist's hand.
It is reef-safe with corals but a threat to small, peaceful fish.
Keep a single fish or one young bonded pair only; never mix it with other clownfish species.
Because of its size and aggression it suits a larger, carefully stocked tank where calmer or similarly bold tankmates can hold their own.
A good fit for
Keepers wanting a large, bold clownfish
Larger reef or FOWLR tanks
Aquarists who can manage aggression
Single-specimen or bonded-pair setups
Common mistakes to avoid
Underestimating adult size and aggression
Mixing with other clownfish species
Keeping two unbonded adults together
Too-small tank causing constant bullying
Is your enclosure big enough?
Minimum volume210 litres (55 US gallons)
CompanyFine alone or with company. Solitary or one bonded pair only
In a reef, stability matters more than any single target number. A parameter moving fast does more damage than a parameter sitting slightly off.
Go now
Any detectable ammonia or nitriteWater change now with matched, mixed and aerated saltwater. Stop feeding. Directly toxic, and a marine system has less margin than a freshwater one.
Now
Temperature or salinity has moved sharplyCorrect slowly, over hours, not minutes. Check the heater and the top-off. The speed of the change does the damage. Correcting fast repeats the injury in the other direction.
Now
Rapid gilling, or a fish hanging in the flow breathing hardIncrease aeration and check temperature and salinity. Warm water holds less oxygen, and a heater failure shows up here first.
Now
Today
White spots, or a fine dusting like icing sugarIdentify which parasite before treating. Most reef tanks cannot be treated in place. The two common parasites look similar and need different handling; velvet can kill a tank in days.
Today
Corals closed for more than a day, or receding tissueTest alkalinity first, and compare it against the last reading rather than a target. Unstable alkalinity is the most commonly cited coral killer, and a swing shows up in the trend, never in a single point.
Today
A new fish added without quarantine now looks unwellRemove it to a separate system today if you can. Nearly every wipeout in a reef tank traces back to a skipped quarantine.
Today
Quarantine every new animal, including corals and inverts. It is the single practice that separates a reef that lasts from a reef that restarts.
This is general guidance for a healthy adult, not a diagnosis. An exotics vet who knows your animal always overrides it — and the time to find one is before you need one.
What it really costs
Setup, monthly, first year and across a whole life, itemised and with the electricity worked out from the actual wattage. Published figures for the same animal disagree by a factor of four, so the calculator shows ranges rather than picking one.
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