About Arowanas
Arowanas (Osteoglossum and Scleropages spp.) are large, predatory surface fish with scales that reflect light like hammered metal. They are ancient fish — often called "living fossils" — and are highly prized in Southeast Asia as symbols of prosperity. Silver Arowanas from South America are the most affordable; Asian Arowanas (including Red, Golden Crossback and Banjar Red) are significantly more expensive.
Tank Size
This is where most new Arowana keepers make a critical error. Juvenile Arowanas are often sold at 10–15cm and placed in 100L tanks. Within a year they will be 50–70cm and need a minimum of 500–700 litres. Adult Silver Arowanas can reach 90cm+ and need tanks of 1,000L or more.
A good rule: the tank width should be at least 1.5× the fish's body length, and tank length should be 3× body length. Arowanas cannot turn quickly and need long tanks.
Arowanas are powerful jumpers. A tight-fitting, heavy lid is essential — they can and do jump out of open tanks and will not survive the fall.
Water Parameters
- Temperature: 26–30°C (Asian Arowanas prefer the higher end)
- pH: 6.5–7.5 for Silver; 6.0–7.0 for Asian
- Hardness: Soft to medium (50–150 ppm TDS)
- Ammonia/Nitrite: 0 ppm at all times
- Nitrate: Below 20 ppm — weekly 20–30% water changes are essential
Filtration
Arowanas produce a very high bioload. Use a filter rated for at least 3–4× your tank volume per hour. Canister filters (Eheim, Fluval, Sobo) are ideal. Many serious Arowana keepers add a sump filter for additional biological capacity. Ensure strong water circulation but without direct strong current onto the fish.
Feeding
Arowanas are carnivores and surface feeders. In the wild they eat insects, frogs and small fish that fall on the water surface. In captivity:
- Juveniles (under 30cm): Crickets, mealworms, small feeder fish, freeze-dried krill
- Sub-adults (30–60cm): Larger insects, medium feeder fish, frozen prawns, pellets
- Adults: Large feeder fish, frogs (occasionally), large pellets, whole prawns
Train your Arowana to accept pellets early — it is far more convenient and nutritionally complete than relying on live food. Hikari and Sera make pellets specifically for large carnivorous fish. Feed once daily and remove uneaten food.
Tank Mates
Arowanas are best kept alone or with large, robust bottom-dwellers that occupy a completely different water level — large plecos, oscar cichlids, or rays. Never keep them with any fish small enough to be eaten. They are also territorial toward other Arowanas unless kept in very large groups in large tanks.
Drop Eye Prevention
"Drop eye" (when one or both eyes droop downward) is common in captive Arowanas, often caused by the fish staring at objects below the tank. Reduce the amount of activity beneath the tank, use a dark tank background, and ensure the tank is at eye level or higher. There is no medical cure once the condition develops.
