Compatibility Overview
Green Terror Cichlid and Koi are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Green Terror Cichlid | Koi | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 50–75°F | ⚠️ 72–75°F (narrow) |
| pH Range | 6.0–8.0 | 7.0–8.5 | ✅ 7.0–8.0 |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 3.9 in | 24 in | ❌ 6× difference |
| Min. Group | 1+ | 2+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
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
Koi — Cyprinus rubrofuscus
Large pond fish that require hundreds of gallons and cool water. Will eat any fish small enough to fit in their mouth.
Frequently Asked Questions
Can Green Terror Cichlid live with Koi?
Generally not recommended. Green Terror Cichlid and Koi are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Green Terror Cichlid and Koi together?
A minimum of 100 gallons is recommended for keeping Green Terror Cichlid and Koi together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Green Terror Cichlid and Koi?
72–75°F (narrow)
Is a Green Terror Cichlid aggressive toward a Koi?
Green Terror Cichlid is aggressive and Koi is peaceful. These animals require different water types and cannot share one aquarium.
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 | 30/100 |
| Ph | 67/100 |
| Temperament | 30/100 |
| Adult Size | 8/100 |
| 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 | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 180 gal | Best when keeping larger schools or reducing territorial pressure. |