Cardinal Tetra and Fire Eel Compatibility Overview
Cardinal Tetra and Fire Eel are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Cardinal Tetra | Fire Eel | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 75โ82ยฐF | โ 75โ82ยฐF |
| pH Range | 4.5โ7.0 | 6.0โ7.0 | โ 6.0โ7.0 |
| Temperament | peaceful | semi | โ ๏ธ Monitor |
| 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
Fire Eel โ Mastacembelus erythrotaenia
The Fire Eel is a stunning, red-bottomed species that requires a spacious tank. They are peaceful bottom feeders and do best in a well-planted, mature aquarium. With a moderate activity level, they can be a great addition to a community tank, but their size and diet may be incompatible with smaller fish.
Frequently Asked Questions
Can Cardinal Tetra live with Fire Eel?
Generally not recommended. Cardinal Tetra and Fire Eel are generally not recommended to be housed together. The adult size gap creates a meaningful predation risk. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Cardinal Tetra and Fire Eel together?
A minimum of 100 gallons is recommended for keeping Cardinal Tetra and Fire Eel together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Fire Eel?
75โ82ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Fire Eel's 75โ82ยฐF.
Is a Cardinal Tetra aggressive toward a Fire Eel?
The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Tank Size for Cardinal Tetra and Fire Eel
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 114 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 180 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 220 gal | Best when keeping larger schools or reducing territorial pressure. |