Cardinal Tetra and Threadfin Rainbowfish Compatibility Overview
Cardinal Tetra and Threadfin Rainbowfish can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Both species are peaceful, and neither poses a major aggression risk to the other. A minimum 20-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Cardinal Tetra | Threadfin Rainbowfish | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 72โ86ยฐF | โ 73โ82ยฐF |
| pH Range | 4.5โ7.0 | 5.0โ8.0 | โ 5.0โ7.0 |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 1.5 in | 1.6 in | โ Similar |
| Min. Group | 6+ | 6+ | See below |
| Min. Tank Size | 20 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
Threadfin Rainbowfish โ Iriatherina werneri
The Threadfin Rainbowfish is a popular choice for freshwater aquariums due to its vibrant colors and peaceful nature. It requires a well-maintained tank with plenty of swimming space and a moderate water flow. These fish are not known to be aggressive and can be kept in community tanks with other peaceful species.
Frequently Asked Questions
Can Cardinal Tetra live with Threadfin Rainbowfish?
Yes, in a well-planned setup. Cardinal Tetra and Threadfin Rainbowfish can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Both species are peaceful, and neither poses a major aggression risk to the other. A minimum 20-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Cardinal Tetra and Threadfin Rainbowfish together?
A minimum of 20 gallons is recommended for keeping Cardinal Tetra and Threadfin Rainbowfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Threadfin Rainbowfish?
73โ82ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Threadfin Rainbowfish's 72โ86ยฐF.
Is a Cardinal Tetra aggressive toward a Threadfin Rainbowfish?
Cardinal Tetra is peaceful and Threadfin Rainbowfish is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Cardinal Tetra and Threadfin Rainbowfish
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 20 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 29 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 55 gal | Best when keeping larger schools or reducing territorial pressure. |