Maroon Clownfish
Amphiprion biaculeatus
Large, boldly coloured and notably aggressive clownfishIntermediate
- Lifespan
- 10-15 years
- Size
- 15-17 cm (6-7 in) female
- Social needs
- Solitary or one bonded pair only
- Time
- Daily feeding; weekly testing/changes
- Cost
- Medium
- Diet
- Omnivore (meaty frozen, pellets, algae)
Overview
What is this animal?
- 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.
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
Enclosure
Minimum 210 litres (55 US gallons)
Fine alone or with company. Solitary or one bonded pair only
- 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.
Supplies
Setup
- Tank, stand and sump
- Return pump and powerheads
- Protein skimmer
- Reef lighting
- Rock and sand
- Salt mix, refractometer and test kits
- Quarantine tank
Ongoing
- Quality small marine pellet
- Frozen mysis shrimp
- Frozen enriched brine shrimp
- Algae-based marine flake
- Vitamin or HUFA soaking supplement
- Small thawing cup and strainer
- Turkey baster for target-feeding
Safe substrate: Aragonite sand · Dry or cured live rock · Bare bottom
Care routine
Daily
- Check salinity, temperature and flow
- Feed small marine portions
- Head-count and look everyone over
- Top up evaporation with fresh water
Weekly
- Service the skimmer and filter socksevery 3 days
- Clean the glass
- Test the water
- Watch the pair's pecking order
Monthly
- Water changeevery 2 weeks
- Calibrate the refractometer
- Check salt, RO/DI and reagents
Less often
- Deep-clean pumps and powerheadsevery 3 months
- Replace RO/DI filter mediaevery 6 months
Vet: Quarterly review with a pair check — every 3 months
Top resources for more info
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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.
Is your enclosure big enough?
Is this urgent?
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
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.
Bedding and substrate
In a marine system the rock and the sand are life support, and how you start them decides the first six months.
Safe
With a caveat
Never
This is our general list for saltwater fish. We have not built one specific to Clownfish yet.
My kit says 0.25 ppm. Is that dangerous?
A liquid kit measures total ammonia, but only the un-ionised fraction is really toxic, and that fraction is governed by pH and temperature — each whole pH unit multiplies it roughly tenfold. So the same reading can be nearly harmless in one tank and lethal in another; this works out which one you are in.
Compare with other animals
The same axes for every animal, side by side — the way the guides are written makes that a fair comparison rather than two articles.
Clownfish, side by side
Same axes, same care guides — the honest way to choose between types.
See all Clownfish side by side →
