Compatibility Overview
Black Ruby Barb and Harlequin Rasbora 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 | Black Ruby Barb | Harlequin Rasbora | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 72–81°F | ✅ 72–79°F |
| pH Range | 6.5–7.5 | 5.5–7.5 | ✅ 6.5–7.5 |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 1.6 in | 1.75 in | ✅ Similar |
| Min. Group | 6+ | 8+ | See below |
| Min. Tank Size | 40 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Black Ruby Barb — Aquarium species
The Black Ruby Barb is a vibrant, active species suitable for beginners. It requires a spacious tank and a school of its own kind to thrive. Its striking colors and lively nature make it a popular choice.
→ Full Black Ruby Barb care guide
Harlequin Rasbora — 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 Black Ruby Barb live with Harlequin Rasbora?
Yes, in a well-planned setup. Black Ruby Barb and Harlequin Rasbora 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 Black Ruby Barb and Harlequin Rasbora together?
A minimum of 40 gallons is recommended for keeping Black Ruby Barb and Harlequin Rasbora together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Black Ruby Barb and Harlequin Rasbora?
72–79°F
Is a Black Ruby Barb aggressive toward a Harlequin Rasbora?
Black Ruby Barb is aggressive and Harlequin Rasbora is peaceful. 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 | 30/100 |
| Adult Size | 100/100 |
| Swim Zone | 68/100 |
| Social Needs | 85/100 |
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. |