Compatibility Overview
Keyhole Cichlid and Rainbow Shark 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 | Keyhole Cichlid | Rainbow Shark | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 72–79°F | ✅ 72–79°F |
| pH Range | 7.0–8.0 | 6.5–7.5 | ⚠️ 7.0–7.5 (narrow) |
| Temperament | semi | semi | ⚠️ Monitor |
| Adult Size | 2.0 in | 6 in | ⚠️ 3.0× difference |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Keyhole Cichlid — Aquarium species
The Keyhole Cichlid is a popular choice for beginners due to its relatively easy care and peaceful temperament. These fish are known for their distinct keyhole marking and vibrant coloration. They do well in a community tank with other peaceful species, but should be provided with plenty of hiding spots to feel secure. With proper care, they can live for sev
→ Full Keyhole Cichlid care guide
Rainbow Shark — Epalzeorhynchos frenatum
Active bottom dweller that becomes territorial at maturity. One per tank; avoid other shark-like or bottom-dwelling species.
Frequently Asked Questions
Can Keyhole Cichlid live with Rainbow Shark?
With significant caution and a larger tank. Keyhole Cichlid and Rainbow Shark 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 Keyhole Cichlid and Rainbow Shark together?
A minimum of 55 gallons is recommended for keeping Keyhole Cichlid and Rainbow Shark together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Keyhole Cichlid and Rainbow Shark?
72–79°F
Is a Keyhole Cichlid aggressive toward a Rainbow Shark?
Keyhole Cichlid is semi and Rainbow Shark 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 | 50/100 |
| Temperament | 62/100 |
| Adult Size | 38/100 |
| 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 | 100 gal | Best when keeping larger schools or reducing territorial pressure. |