Silver Arowana
Osteoglossum bicirrhosum
A magnificent surface predator that grows enormous - for huge tanks only.
| Difficulty | Advanced |
| Min. Tank Size | 1000 L |
| Temperature | 24.0–30.0 °C |
| pH Range | 6.0–7.5 |
| Max Size | 90.0 cm |
| Lifespan | 10-15 years |
| Diet | Carnivore |
| Temperament | Aggressive |
Overview
The Silver Arowana (Osteoglossum bicirrhosum) is a magnificent surface predator that grows enormous - for huge tanks only. It is a popular choice among Australian aquarists, reaching around 90 cm and living roughly 10-15 years when properly cared for.
This complete guide covers how to keep the Silver Arowana successfully - tank size and setup, water parameters, the best foods (including recommended brands), suitable tank mates, breeding, sexing and the health issues to watch for. It is rated Advanced to care for.
Natural Habitat & Origin
This species is an 'oddball' - an unusual, often ancient or predatory fish from tropical rivers. It needs a large tank, a very secure lid, plenty of cover, and pristine, well-oxygenated water.
Matching the temperature, water chemistry and cover a species evolved with is the simplest route to keeping it healthy and seeing its natural behaviour and colour.
Tank Size & Aquarium Setup
Provide a minimum of 1000 litres for the Silver Arowana. Give it a large footprint with sight-breaks and cover to reduce territorial aggression.
A tight-fitting lid is essential - this species is a capable jumper.
Live plants, driftwood and shaded retreats give security and show off the fish's colours against a natural backdrop.
Always add fish only to a fully cycled, mature tank with stable biological filtration. Provide strong, well-oxygenated flow for this active, oxygen-hungry species.
Water Parameters
Keep the Silver Arowana in stable water at 24-30 °C with a pH of 6.0-7.5. It adapts to a moderate range, so stability matters more than an exact figure.
Test regularly: ammonia and nitrite must read zero, and nitrate should be kept low with routine partial water changes. Always dechlorinate and temperature-match new water, because sudden swings cause far more illness than water that is stable but slightly imperfect.
Diet & Feeding
The Silver Arowana is a carnivore and needs a protein-rich, meaty diet.
In Australia, good options include Hikari Carnivore/Massivore pellets, API Carnivore food and Dymax frozen bloodworm, brine shrimp, krill and mussel. Feed small amounts once or twice a day (only what is cleared in a minute or two), vary the diet for the best colour and health, and avoid overfeeding, which is the leading cause of poor water quality.
Temperament & Tank Mates
The Silver Arowana is aggressive and is best kept alone or only with very carefully chosen, equally robust tank mates in a large tank. Avoid keeping it with small or timid species it will bully or eat.
Breeding
The Silver Arowana is a mouthbrooder - the parent holds the fertilised eggs and fry safely in its mouth until they can swim and feed on their own.
Even if you are not planning to breed it, recognising this behaviour helps you understand what you are seeing and respond well - for example by adding cover for fry or giving a guarding pair extra space.
How to Tell Males from Females
These species are usually very difficult to sex visually, with no reliable external differences outside breeding condition.
Common Health Problems
Like most aquarium species it can suffer from white spot (ich), fin rot and fungal or bacterial infections, almost always triggered by stress or poor water quality. Quarantine new arrivals for 2-4 weeks and watch daily for early signs such as loss of appetite, unusual hiding, clamped fins or laboured breathing - caught early, most issues are very treatable.
Prevention beats cure: keep water pristine, avoid overstocking and overfeeding, quarantine new arrivals, and act at the first sign of trouble.
Is the Silver Arowana Right for You?
The Silver Arowana suits keepers with some experience and a stable, mature, appropriately sized tank, as long as you can provide at least 1000 litres, water at 24-30 °C and pH 6.0-7.5, the right diet and suitable tank mates.
Meet those needs and the Silver Arowana will reward you for around 10-15 years. Use our free aquarium calculators to plan your setup, and explore our other fish, plant and disease guides to build a thriving aquarium.
