Compatibility Overview
Harlequin Rasbora and Zebra Loach 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 75-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Harlequin Rasbora | Zebra Loach | Verdict |
|---|---|---|---|
| Temperature | 72–81°F | 72–79°F | ✅ 72–79°F |
| pH Range | 5.5–7.5 | 6.5–7.5 | ✅ 6.5–7.5 |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.75 in | 4.7 in | ⚠️ 2.7× difference |
| Min. Group | 8+ | 1+ | See below |
| Min. Tank Size | 75 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
Zebra Loach — Aquarium species
The Zebra Loach is a popular community fish known for its striped appearance and peaceful nature. It requires a spacious tank and is best kept in groups of at least three. These loaches are adaptable and can thrive in a variety of freshwater conditions. They are bottom feeders and help to keep the aquarium clean by eating algae and uneaten food.
Frequently Asked Questions
Can Harlequin Rasbora live with Zebra Loach?
Yes, in a well-planned setup. Harlequin Rasbora and Zebra Loach 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 75-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Harlequin Rasbora and Zebra Loach together?
A minimum of 75 gallons is recommended for keeping Harlequin Rasbora and Zebra Loach together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Zebra Loach?
72–79°F
Is a Harlequin Rasbora aggressive toward a Zebra Loach?
Harlequin Rasbora is peaceful and Zebra Loach 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 | 72/100 |
| Swim Zone | 92/100 |
| 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 | 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. |