Red Tail Arowana
Scleropages formosus
The Red Tail Arowana (Scleropages formosus) is an aggressive fish that's best left to experienced keepers. Give it a tank of at least 900 litres (238 US gallons), water held at 75-86°F, and a pH of 6-7.5.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
Southeast Asia
- East & Southeast Asia
Regional colours match the stocking calculator's origin map.
Red Tail Arowana Tank Setup
Treat 900 litres (238 US gallons) as a starting point - big predators need length, strong filtration, and a secure lid. Hold the water at 75-86°F and pH 6-7.5, and assume anything small enough to swallow will eventually be eaten. They grow to around 90 cm, so plan the tank size and filtration for a full-grown adult rather than the small juvenile you see in the shop.
What Do Red Tail Arowanas Eat?
They're meat-eaters, so feed good-quality frozen or gel foods rather than relying on generic flake. Go easy on portions - leftover protein fouls the water faster than plant foods do.
Red Tail Arowana Tank Mates
Extremely large species; unsuitable for most home aquariums; requires very large tank and secure lid The Red Tail Arowana is aggressive, which is the first thing to weigh up when you choose tank mates. It's predatory, so anything small enough to fit in its mouth will be treated as food rather than a companion. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.
Are Red Tail Arowanas Good for Beginners?
Not a sensible first purchase. Get the tank cycled, keep easier fish stable for a year, then revisit if you still want the extra work this species demands.
Red Tail Arowana - frequently asked questions
What size tank do Red Tail Arowanas need?
Red Tail Arowanas need a tank of at least 900 litres (238 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.
What water parameters do Red Tail Arowanas need?
Keep them at 75-86°F with a pH of 6-7.5, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.
What do Red Tail Arowanas eat?
Red Tail Arowanas are meat-eaters. Feed good-quality frozen or gel foods rather than relying on generic flake, and don't overfeed. Feed small amounts once or twice a day, and remove anything they don't eat.
Are Red Tail Arowanas good for beginners?
Red Tail Arowanas are not a beginner species. They need precise conditions and consistent maintenance, so build experience with hardier fish before keeping them.
Common mistakes with Red Tail Arowanas
- Underestimating tank size - the minimum footprint is 900 litres (238 US gallons); impulse buying into a smaller tank leads to stress and shortened lifespan.
- Adding to a new tank - Red Tail Arowanas need a fully cycled, stable aquarium; ammonia spikes in new setups are usually fatal.
Building a community? Run the full list through the stocking calculator before you add anything else.
Great tank mates
Chosen from temperament, overlapping temperature/pH bands, plausible minimum tank footprints, and size versus yours in App-aquatic data. Hobby nuance always wins - verify stocking and temperament before purchasing.
Fish to avoid mixing with Red Tail Arowanas
These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.
- OscarPredator - Oscar will eat or injure smaller tank mates
- Serpae TetraFin nipper - will shred the fins of peaceful fish
- Zebra DanioFin nipper - will shred the fins of peaceful fish
