Harlequin Rasbora and Silver Arowana Compatibility Overview
Harlequin Rasbora and Silver Arowana are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Harlequin Rasbora is peaceful and Silver Arowana is aggressive. Expect chasing and fin damage unless the tank is oversized, heavily planted, and watched closely. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Harlequin Rasbora | Silver Arowana | Verdict |
|---|---|---|---|
| Temperature | 72โ81ยฐF | 68โ86ยฐF | โ 72โ81ยฐF |
| pH Range | 5.5โ7.5 | 5.0โ7.5 | โ 5.5โ7.5 |
| Temperament | peaceful | aggressive | โ Risk |
| Adult Size | 1.75 in | 31.5 in | โ 18ร difference |
| Min. Group | 8+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Harlequin Rasbora โ Trigonostigma heteromorpha
Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.
โ Full Harlequin Rasbora care guide
Silver Arowana โ Osteoglossum bicirrhosum
The Silver Arowana is a majestic and unique fish known for its striking appearance and size. It is a large, predatory fish that requires a spacious tank and specific water conditions. While not a community fish, it can be kept with compatible, larger species. They are sensitive to stress and require careful water quality management.
Frequently Asked Questions
Can Harlequin Rasbora live with Silver Arowana?
Generally not recommended. Harlequin Rasbora and Silver Arowana are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Harlequin Rasbora is peaceful and Silver Arowana is aggressive. Expect chasing and fin damage unless the tank is oversized, heavily planted, and watched closely. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Harlequin Rasbora and Silver Arowana together?
A minimum of 100 gallons is recommended for keeping Harlequin Rasbora and Silver Arowana together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Silver Arowana?
72โ81ยฐF โ inside Harlequin Rasbora's 72โ81ยฐF and Silver Arowana's 68โ86ยฐF.
Is a Harlequin Rasbora aggressive toward a Silver Arowana?
The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Tank Size for Harlequin Rasbora and Silver Arowana
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 250 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 350 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 450 gal | Best when keeping larger schools or reducing territorial pressure. |