Compatibility Overview
Cardinal Tetra and Green Terror 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 | Cardinal Tetra | Green Terror Cichlid | Verdict |
|---|---|---|---|
| Temperature | 73–82°F | 72–82°F | ✅ 73–82°F |
| pH Range | 4.5–7.0 | 6.0–8.0 | ✅ 6.0–7.0 |
| Temperament | peaceful | aggressive | ❌ Risk |
| Adult Size | 1.5 in | 3.9 in | ⚠️ 2.6× difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Cardinal Tetra — Paracheirodon axelrodi
Brilliant red-and-blue schooling fish from the Rio Negro. Prefers soft, acidic, warm water — a natural companion for discus.
→ Full Cardinal Tetra care guide
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
Frequently Asked Questions
Can Cardinal Tetra live with Green Terror Cichlid?
With significant caution and a larger tank. Cardinal Tetra and Green Terror 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 Cardinal Tetra and Green Terror Cichlid together?
A minimum of 55 gallons is recommended for keeping Cardinal Tetra and Green Terror Cichlid together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Green Terror Cichlid?
73–82°F
Is a Cardinal Tetra aggressive toward a Green Terror Cichlid?
Cardinal Tetra is peaceful and Green Terror Cichlid is aggressive. 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 | 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 | 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. |