Cardinal Tetra and Swordtail Compatibility Overview
Cardinal Tetra and Swordtail can potentially coexist, but the combination requires careful attention. Their usable pH overlap is narrow and requires stable, tested water. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
| Factor | Cardinal Tetra | Swordtail | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 65โ80ยฐF | โ 73โ80ยฐF |
| pH Range | 4.5โ7.0 | 7.0โ8.3 | โ ๏ธ 7.0โ7.0 (narrow) |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 1.5 in | 5 in | โ ๏ธ 3.3ร difference |
| Min. Group | 6+ | 3+ | See below |
| Min. Tank Size | 75 gallons (for both species) | โ | |
Compatibility Positives
Caution Points
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
Swordtail โ Xiphophorus hellerii
Hardy livebearer with a distinctive elongated lower tail fin in males. Peaceful community fish that tolerate a wide temperature range.
Frequently Asked Questions
Can Cardinal Tetra live with Swordtail?
With significant caution and a larger tank. Cardinal Tetra and Swordtail can potentially coexist, but the combination requires careful attention. Their usable pH overlap is narrow and requires stable, tested water. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Cardinal Tetra and Swordtail together?
A minimum of 75 gallons is recommended for keeping Cardinal Tetra and Swordtail together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Swordtail?
73โ80ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Swordtail's 65โ80ยฐF.
Is a Cardinal Tetra aggressive toward a Swordtail?
Cardinal Tetra is peaceful and Swordtail is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Cardinal Tetra and Swordtail
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 75 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 125 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 150 gal | Best when keeping larger schools or reducing territorial pressure. |