Compatibility Overview
Harlequin Rasbora and Peacock Cichlid 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 55 gallons), dense planting, and close monitoring are essential.
| Factor | Harlequin Rasbora | Peacock Cichlid | Verdict |
|---|---|---|---|
| Temperature | 72–81°F | 75–81°F | ✅ 75–81°F |
| pH Range | 5.5–7.5 | 7.5–8.5 | ⚠️ 7.5–7.5 (narrow) |
| Temperament | peaceful | aggressive | ❌ Risk |
| Adult Size | 1.75 in | 3.1 in | ✅ Similar |
| Min. Group | 8+ | 1+ | See below |
| Min. Tank Size | 55 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
Peacock Cichlid — Aquarium species
The Peacock Cichlid, Aulonocara nyassae, is a stunning fish with vibrant blue and yellow colors. These fish are known for their aggression and require a mature and well-maintained tank. They are best kept in pairs or in a species-specific tank. Careful attention must be given to water parameters and tank setup to ensure their health and well-being.
Frequently Asked Questions
Can Harlequin Rasbora live with Peacock Cichlid?
With significant caution and a larger tank. Harlequin Rasbora and Peacock Cichlid 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 55 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Harlequin Rasbora and Peacock Cichlid together?
A minimum of 55 gallons is recommended for keeping Harlequin Rasbora and Peacock Cichlid together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Harlequin Rasbora and Peacock Cichlid?
75–81°F
Is a Harlequin Rasbora aggressive toward a Peacock Cichlid?
Harlequin Rasbora is peaceful and Peacock Cichlid is aggressive. Their preferred pH ranges are difficult to reconcile.
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 | 0/100 |
| Temperament | 30/100 |
| 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 | 55 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 75 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 125 gal | Best when keeping larger schools or reducing territorial pressure. |