Silver Arowana: The Dragon Fish That Jumps Out of Your Tank
Silver arowanas are majestic fish, but their size, jumping ability, and predatory instinct make them unsuitable for any but the largest dedicated setups.
Arowana ownership reality check
Consideration
| Consideration | What it means | Common beginner mistake | Takeaway |
|---|---|---|---|
| Tank size | Adults need 250+ gallons with swimming space | Buying a juvenile for a 55-gallon | The juvenile will outgrow a small tank within a year |
| Jumping | Arowanas can leap several feet — lids must be heavy and secure | Using a standard glass lid or mesh | They can punch through lightweight covers |
| Tankmates | Almost any fish that fits in their mouth is food | Wanting a community arowana tank | Treat them as a solo specimen or with very large, robust fish |
| Commitment | 15-20 year lifespan in good conditions | Impulse purchase without long-term plan | This is a multi-decade fish |
Arowana care rules
| Plan for a 250+ gallon adult tank from the start | |
| Install a heavy, lockable lid rated for arowana strength | |
| Expect to keep it solo or with very large tankmates only | |
| Budget for high-quality protein-rich food long-term | |
| Research local regulations — arowana restrictions vary | |
| Assume a store juvenile will stay at that size | |
| Use a standard aquarium hood or mesh lid | |
| Keep with small community fish as a display |
The silver arowana is a commitment that most hobbyists are not prepared for. A three-foot predatory fish that jumps and lives two decades is not a casual community addition.
Standard glass lids and mesh covers are not arowana-proof. A startled fish can easily break through them and land on the floor, where survival is unlikely.
Silver arowanas (Osteoglossum bicirrhosum) are predatory surface fish that reach 3-4 feet in captivity and require 300+ gallon tanks as adults. They are spectacular animals for serious aquarists with space and budget. Their primary hazard: arowanas are legendary jumpers -- uncovered tanks mean dead arowanas, without exception.
| Requirement | Specification | Notes |
|---|---|---|
| Min tank (adult) | 300 gal (500 gal preferred) | Must turn fully; width is critical — head-drop from glass impacts |
| Lid | Tight-fit aluminum mesh + weights | 24-in vertical jump capacity; any gap will be found |
| Temperature / pH | 75–82°F / pH 6.0–7.0 | Amazonian blackwater; hardness 1–10 dGH; zero NH3/NO2 tolerance |
| Diet | Train to sinking pellets early | Live feeders carry disease; feed with tongs — feeding response is aggressive |
The Jump Problem
Arowanas are surface predators that hunt by launching themselves from the water to catch insects, birds, and small animals on overhanging branches. This behavior is fully intact in captivity. Any gap in a tank lid will be found and exploited. A startled arowana can clear a 24-inch vertical jump. Tank covers must be tight-fitting, heavy, and secured -- even briefly lifting the lid for feeding can result in a jump. Commercial arowana keepers use custom aluminum mesh covers with weighted edges. This is not an exaggeration: online arowana communities document dozens of jump deaths per year from experienced keepers who looked away for 30 seconds.
Tank Size Reality
Juveniles (6-12 inches) are sold in pet stores in manageable sizes, but growth is rapid -- 2 inches per month in optimal conditions. Adult silver arowanas reach 36-48 inches. A 300-gallon tank (96 x 24 x 30 inches) is minimum for a single adult; 500 gallons is preferable. This is not a beginner species or an apartment species. Tank width matters -- arowanas need turning room, and a fish that cannot turn hits the glass repeatedly, developing head-drop (a neurological condition from repeated trauma to the optic region).
Water Quality
Origin: blackwater rivers of the Amazon basin -- warm, soft, acidic. Target: temperature 75-82F, pH 6.0-7.0, hardness 1-10 dGH. High sensitivity to ammonia and nitrite -- zero tolerance even at trace levels. Massive filtration required: a single arowana has the bioload of many smaller fish. Canister filters rated for 2-3x the actual tank volume, combined with sump filtration, is standard. Weekly 25-30% water changes. Nitrates should stay below 20 ppm.
Diet
Arowanas are obligate carnivores. Wild diet: insects, small fish, frogs, small birds. Captive diet: feeder fish (risk of disease -- quarantine feeders), large crickets, superworms, krill, whole prawns, and eventually trained to accept pellets (Hikari Arowana or similar high-protein floating pellets). Feeding response is aggressive -- feed with tongs. Train off live feeders toward prepared foods early in captivity; long-term live feeder use increases disease risk and is nutritionally inconsistent.
Tankmates
Arowanas eat anything that fits in their mouth -- up to 1/3 of their own body length. Safe tankmates must be too large to swallow and not fin-nippers: large stingrays, large oscars (with caution), large Pacu, large Plecostomus. Never house with small fish, cichlids that attack surface fish, or aggressive species that nip long fins. Many experienced keepers house arowanas alone -- the combination of finding compatible tankmates and managing their needs in a large enough system adds complexity not worth it for most.
Sources: Fishbase Osteoglossum bicirrhosum species account; Dawes J, Arowanas, in The Complete Aquarium Fish Handbook; specialist documentation from Arowana Society communities; Kottelat M, Whitten AJ, Freshwater Fishes of Western Indonesia and Sulawesi.