Arowana
Osteoglossum bicirrhosum
Min Tank Size
950L
Adult Size
90 cm
Lifespan
15 years
About
Silver Arowana come from the floodplains and slow blackwater rivers of the Amazon basin, and there's really nothing else quite like them in the hobby. They're almost prehistoric looking, with large reflective scales that flash silver-white under light, a long sinuous body, and a massive upturned mouth perfectly designed for snatching prey from the surface. Those two short chin barbels help them sense vibrations and prey above the waterline. They're genuine giants, routinely reaching 90cm in captivity and sometimes pushing beyond that.
0 range, with temperatures held between 24 and 30 degrees Celsius. They produce an enormous amount of waste, so filtration needs to be seriously oversized and water changes need to be frequent and large.
Diet should be meaty and varied, things like large crickets, earthworms, whole shrimp, and quality carnivore pellets. Live feeder fish aren't recommended long-term because of parasite risk and the behavioral problems they can trigger.
These fish are sensitive to stress and don't tolerate sudden changes in lighting, water chemistry, or tank conditions well. They're not a display fish you can just set up and forget. Keeping one properly is a serious long-term commitment, both financially and in terms of tank space.
Water Parameters
Temperature
°CpH
GH
dGHKH
dKHSwimming Level
Flow Preference
Keeping multiple Arowana together
Arowanas are commonly kept alone due to extreme size, predatory nature, and the massive tank required for any community setup.
Compatibility
Tankmates need to be large enough not to be eaten and robust enough to hold their own. Good options include large cichlids like peacock bass or oscars, big catfish like shovelnose or redtail catfish, and large plecos. Avoid anything under roughly 15 to 20cm, as it'll likely disappear overnight. Slow, long-finned fish at the surface are a bad idea since they'll compete for the arowana's zone and may provoke stress responses. The tank needs to be genuinely massive, well over 946 liters, for any community setup to function. Many experienced keepers house them alone.
Commonly kept with
Species this one is most often paired withCommonly tried but avoid
Often paired, but shouldn't beCare Notes
The most common mistake is buying a juvenile arowana thinking the tank size requirement is years away. They grow fast, often 30cm or more in the first year, and outgrow standard aquariums quickly. Filtration is almost always the next failure point since the bioload is enormous. A single arowana needs turnover rates most people would use for a heavily stocked cichlid tank. The secure lid issue kills fish regularly. Arowanas will find any gap and launch themselves out without warning. Don't underestimate this.
Behavior & Aggression
Arowanas aren't aggressive in the traditional fin-nipping sense, but they're unambiguously predatory. Anything small enough to be considered prey will be eaten, full stop. Toward tankmates of comparable or larger size, they're more indifferent than hostile, but they can become territorial about surface space. Two arowanas together almost always ends badly, with one harassing the other relentlessly until injury or death occurs. Stress from overcrowding or reflections in the glass can also cause them to thrash and injure themselves.
Things to Know
- Powerful jumper, tank must have a very heavy, secure lid at all times
- Will eat any fish or invertebrate small enough to fit in its mouth
- Adults can exceed 90cm and require custom or very large commercial tanks
- Highly sensitive to poor water quality, needs heavy filtration and frequent changes
- Can be kept singly only, adults will fight and kill other arowanas
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