Compatibility Overview
Keyhole Cichlid and Threadfin Rainbowfish 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 20-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Keyhole Cichlid | Threadfin Rainbowfish | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 72–82°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 | 2.0 in | ✅ Similar |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 20 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
Threadfin Rainbowfish — Aquarium species
The Threadfin Rainbowfish is a popular choice for freshwater aquariums due to its vibrant colors and peaceful nature. It requires a well-maintained tank with plenty of swimming space and a moderate water flow. These fish are not known to be aggressive and can be kept in community tanks with other peaceful species. Regular water changes and a balanced diet ar
Frequently Asked Questions
Can Keyhole Cichlid live with Threadfin Rainbowfish?
Yes, in a well-planned setup. Keyhole Cichlid and Threadfin Rainbowfish 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 20-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Keyhole Cichlid and Threadfin Rainbowfish together?
A minimum of 20 gallons is recommended for keeping Keyhole Cichlid and Threadfin Rainbowfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Keyhole Cichlid and Threadfin Rainbowfish?
72–79°F
Is a Keyhole Cichlid aggressive toward a Threadfin Rainbowfish?
Keyhole Cichlid is semi and Threadfin Rainbowfish 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 | 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 | 20 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 29 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 40 gal | Best when keeping larger schools or reducing territorial pressure. |