Harlequin Rasbora and Molly Compatibility Overview
Harlequin Rasbora and Molly can potentially coexist, but the combination requires careful attention. Their usable pH overlap is narrow and requires stable, tested water. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
| Factor | Harlequin Rasbora | Molly | Verdict |
|---|---|---|---|
| Temperature | 72โ81ยฐF | 72โ82ยฐF | โ 72โ81ยฐF |
| pH Range | 5.5โ7.5 | 7.5โ8.5 | โ ๏ธ 7.5โ7.5 (narrow) |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 1.75 in | 4 in | โ ๏ธ 2.3ร difference |
| Min. Group | 8+ | 3+ | See below |
| Min. Tank Size | 75 gallons (for both species) | โ | |
Compatibility Positives
Caution Points
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
Molly โ Poecilia sphenops
Hardy livebearers that prefer alkaline, hard water โ sometimes slightly brackish. Prolific breeders; peaceful community fish.
Frequently Asked Questions
Can Harlequin Rasbora live with Molly?
With significant caution and a larger tank. Harlequin Rasbora and Molly can potentially coexist, but the combination requires careful attention. Their usable pH overlap is narrow and requires stable, tested water. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Harlequin Rasbora and Molly together?
A minimum of 75 gallons is recommended for keeping Harlequin Rasbora and Molly together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Molly?
72โ81ยฐF โ inside Harlequin Rasbora's 72โ81ยฐF and Molly's 72โ82ยฐF.
Is a Harlequin Rasbora aggressive toward a Molly?
Harlequin Rasbora is peaceful and Molly is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Harlequin Rasbora and Molly
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 75 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 125 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 150 gal | Best when keeping larger schools or reducing territorial pressure. |