Compatibility Overview
Green Terror Cichlid and Harlequin Rasbora can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
| Factor | Green Terror Cichlid | Harlequin Rasbora | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 72–81°F | ✅ 72–81°F |
| pH Range | 6.0–8.0 | 5.5–7.5 | ✅ 6.0–7.5 |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 3.9 in | 1.75 in | ⚠️ 2.2× difference |
| Min. Group | 1+ | 8+ | See below |
| Min. Tank Size | 75 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Green Terror Cichlid — Aquarium species
The Green Terror Cichlid is a popular choice for experienced aquarists due to its striking appearance and vibrant colors. They are known for their aggression and should be kept in a species-specific tank. Their tall, laterally compressed bodies and vivid coloration make them visually appealing but require careful handling due to their potentially aggressive
→ Full Green Terror Cichlid 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 Green Terror Cichlid live with Harlequin Rasbora?
With significant caution and a larger tank. Green Terror Cichlid and Harlequin Rasbora can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Green Terror Cichlid and Harlequin Rasbora together?
A minimum of 75 gallons is recommended for keeping Green Terror Cichlid and Harlequin Rasbora together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Green Terror Cichlid and Harlequin Rasbora?
72–81°F
Is a Green Terror Cichlid aggressive toward a Harlequin Rasbora?
Green Terror Cichlid 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 | 75/100 |
| Temperament | 30/100 |
| Adult Size | 72/100 |
| 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 | 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. |