Silver arowana care requires a large tank, pristine water, and an understanding of this fish’s predatory nature. The silver arowana (Osteoglossum bicirrhosum) is a surface-hunting predator from the Amazon River basin that can reach 35 inches (90 cm) in captivity. It is one of the most dramatic freshwater fish in the hobby — and one of the most demanding to keep correctly.
This silver arowana care guide covers tank size, water parameters, feeding, tankmates, common health problems, and the key mistakes that cause most arowana deaths in home aquariums.
Silver Arowana Care — Quick Reference
| Parameter | Requirement |
|---|---|
| Adult size | Up to 35 inches (90 cm) |
| Tank size | 250 gallons (950 L) minimum for adults |
| Water temperature | 75–82°F (24–28°C) |
| pH | 6.0–7.0 |
| Hardness | 1–8 dGH (soft water) |
| Filtration | Heavy — canister filter, high turnover |
| Diet | Carnivore — insects, fish, shrimp |
| Lifespan | 10–15 years |
| Temperament | Predatory — will eat small tankmates |
Tank Size — The Most Critical Factor
Silver arowana grow fast. A juvenile sold at 4–6 inches can reach 24 inches within the first year under good conditions. An adult arowana needs an absolute minimum of 250 gallons (950 litres), with a tank length of at least 8 feet (240 cm) to allow the fish to turn comfortably. Most experienced keepers recommend 300–500 gallons for a single adult arowana.
Arowanas are strong jumpers. Any arowana tank must have a heavy, secured lid — arowanas can launch themselves clear out of open tanks and die within minutes on the floor. Use a tight-fitting lid with no gaps.
Water Quality and Filtration
Silver arowanas come from the blackwater rivers of the Amazon — soft, slightly acidic water with low mineral content. Aim for pH 6.0–7.0 and water hardness of 1–8 dGH. Temperature should be kept at 75–82°F (24–28°C).
Filtration must be powerful. Arowanas produce significant waste and are highly sensitive to ammonia and nitrite. Use a high-capacity canister filter rated for at least twice the tank volume and perform 25–30% water changes weekly. Test water parameters weekly with a quality test kit.
What to Feed Silver Arowana
In the wild, silver arowanas are surface predators that eat insects, small fish, frogs, and birds that venture near the water. In the aquarium, feed a varied carnivore diet:
- Juvenile (under 6 inches): live or frozen baby brine shrimp, small crickets, bloodworms
- Sub-adult (6–18 inches): crickets, mealworms, small feeder fish (from disease-free sources), large earthworms, frozen prawns
- Adult: large earthworms, prawns, large crickets, frozen smelt, pellets (train early)
Train your arowana to accept high-quality pellets from an early age — this provides a complete diet and reduces dependence on feeder fish, which carry a high disease risk. Feed juveniles once or twice daily; adults every 1–2 days. Arowana stomachs are large but overfeeding causes fatty liver disease over time.
Silver Arowana Tankmates
Silver arowanas will eat anything that fits in their mouth. In a large enough tank (300+ gallons), suitable tankmates include:
- Large cichlids (Oscar, green terror, jaguar cichlid)
- Large plecos (royal pleco, sailfin pleco)
- Large catfish (redtail catfish — in extremely large tanks only)
- Large barbs (tinfoil barbs, silver dollar fish)
Never keep silver arowanas with small fish, tetras, guppies, bettas, or any fish that fits in the arowana’s mouth. Arowanas are also territorial with other arowanas — single specimens are recommended for home aquariums.
Common Silver Arowana Health Problems
- Drop eye — the most common arowana condition; eyes drop downward from fixating on objects below the water line. Prevent by keeping décor off the bottom and using dark substrate; some breeders use lights below the tank to keep the fish looking up.
- Mouth gape / jaw deformity — caused by biting tank glass repeatedly; ensure the tank is long enough for the fish to turn without hitting the ends
- Fin rot — caused by poor water quality; treat with water changes and antibiotics if severe
- Ich — white spots from temperature fluctuation; treat by raising temperature and using ich medication
- Fatty liver — from overfeeding feeder fish high in fat; switch to earthworms, prawns, and pellets