Cardinal Tetra and Clown Knifefish Compatibility Overview
Cardinal Tetra and Clown Knifefish are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Their pH ranges overlap only partly, so aim for the shared band and keep it steady. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Cardinal Tetra | Clown Knifefish | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 68โ82ยฐF | โ 73โ82ยฐF |
| pH Range | 4.5โ7.0 | 6.0โ8.0 | โ 6.0โ7.0 |
| Temperament | peaceful | aggressive | โ Risk |
| Adult Size | 1.5 in | 39.4 in | โ 26ร difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Cardinal Tetra โ Paracheirodon axelrodi
Brilliant red-and-blue schooling fish from the Rio Negro. Prefers soft, acidic, warm water โ a natural companion for discus.
โ Full Cardinal Tetra care guide
Clown Knifefish โ Chitala ornata
The Clown Knifefish is a unique and visually striking species known for its slender body and distinctive coloration. It is a solitary fish that requires a spacious tank to thrive. With a moderate activity level and low aggression, it can be a suitable addition to a community tank with similarly peaceful species.
Frequently Asked Questions
Can Cardinal Tetra live with Clown Knifefish?
Generally not recommended. Cardinal Tetra and Clown Knifefish are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Their pH ranges overlap only partly, so aim for the shared band and keep it steady. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Cardinal Tetra and Clown Knifefish together?
A minimum of 100 gallons is recommended for keeping Cardinal Tetra and Clown Knifefish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Clown Knifefish?
73โ82ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Clown Knifefish's 68โ82ยฐF.
Is a Cardinal Tetra aggressive toward a Clown Knifefish?
The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Tank Size for Cardinal Tetra and Clown Knifefish
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 300 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 450 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 550 gal | Best when keeping larger schools or reducing territorial pressure. |