Discus and Harlequin Rasbora Compatibility Overview
Discus and Harlequin Rasbora are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. There is no shared temperature: Discus needs 82โ88ยฐF and Harlequin Rasbora needs 72โ81ยฐF. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Discus | Harlequin Rasbora | Verdict |
|---|---|---|---|
| Temperature | 82โ88ยฐF | 72โ81ยฐF | โ No overlap |
| pH Range | 5.0โ7.0 | 5.5โ7.5 | โ 5.5โ7.0 |
| Temperament | semi | peaceful | โ ๏ธ Monitor |
| Adult Size | 8 in | 1.75 in | โ 5ร difference |
| Min. Group | 5+ | 8+ | See below |
| Min. Tank Size | 100 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Discus โ Symphysodon spp.
The 'king of the aquarium' โ beautiful but demanding. Requires very warm, soft, acidic water that excludes most community fish.
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.
Frequently Asked Questions
Can Discus live with Harlequin Rasbora?
Generally not recommended. Discus and Harlequin Rasbora are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. There is no shared temperature: Discus needs 82โ88ยฐF and Harlequin Rasbora needs 72โ81ยฐF. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Discus and Harlequin Rasbora together?
A minimum of 100 gallons is recommended for keeping Discus and Harlequin Rasbora together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Discus and Harlequin Rasbora?
There is no safe shared range: Discus needs 82โ88ยฐF and Harlequin Rasbora needs 72โ81ยฐF.
Is a Discus aggressive toward a Harlequin Rasbora?
The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Tank Size for Discus and Harlequin Rasbora
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 220 gal | Best when keeping larger schools or reducing territorial pressure. |