Compatibility Overview
Harlequin Rasbora and Moonlight Gourami can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 40-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Harlequin Rasbora | Moonlight Gourami | Verdict |
|---|---|---|---|
| Temperature | 72–81°F | 72–82°F | ✅ 72–81°F |
| pH Range | 5.5–7.5 | 6.5–7.5 | ✅ 6.5–7.5 |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.75 in | 2.0 in | ✅ Similar |
| Min. Group | 8+ | 1+ | See below |
| Min. Tank Size | 40 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Harlequin Rasbora — Trigonostigma heteromorpha
Active mid-level schooling fish with a distinctive black triangular patch. One of the best all-around community tank fish.
→ Full Harlequin Rasbora care guide
Moonlight Gourami — Aquarium species
The Moonlight Gourami is a beautiful freshwater fish known for its silvery blue color and red eyes. It is a peaceful community fish suitable for beginners and can thrive in a well-maintained aquarium. These fish are sensitive to water quality and require a spacious tank with plenty of swimming space. They are not known to school and prefer to have their terr
Frequently Asked Questions
Can Harlequin Rasbora live with Moonlight Gourami?
Yes, in a well-planned setup. Harlequin Rasbora and Moonlight Gourami can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 40-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Harlequin Rasbora and Moonlight Gourami together?
A minimum of 40 gallons is recommended for keeping Harlequin Rasbora and Moonlight Gourami together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Moonlight Gourami?
72–81°F
Is a Harlequin Rasbora aggressive toward a Moonlight Gourami?
Harlequin Rasbora is peaceful and Moonlight Gourami is semi. No major aggression issues are expected between these species.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 100/100 |
| Ph | 100/100 |
| Temperament | 75/100 |
| Adult Size | 100/100 |
| Swim Zone | 68/100 |
| Social Needs | 92/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 40 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 55 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 90 gal | Best when keeping larger schools or reducing territorial pressure. |