Cardinal Tetra and Royal Gramma Compatibility Overview
Cardinal Tetra and Royal Gramma are generally not recommended to be housed together. One of these is a marine species and the other is not; they cannot share one aquarium. Their pH ranges do not meet: Cardinal Tetra wants 4.5โ7.0 and Royal Gramma wants 8.1โ8.4. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Cardinal Tetra | Royal Gramma | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 72โ82ยฐF | โ 73โ82ยฐF |
| pH Range | 4.5โ7.0 | 8.1โ8.4 | โ No overlap |
| Temperament | peaceful | semi | โ ๏ธ Monitor |
| Adult Size | 1.5 in | 3.0 in | โ ๏ธ 2.0ร difference |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 20 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
Royal Gramma โ Gramma loreto
The Royal Gramma, known for its vibrant blue coloration, is a popular saltwater fish among beginners and experienced aquarists alike. It requires a well-maintained tank with plenty of swimming space and a moderate current. With a peaceful temperament and a relatively easy care routine, the Royal Gramma can be a great addition to a community tank.
Frequently Asked Questions
Can Cardinal Tetra live with Royal Gramma?
Generally not recommended. Cardinal Tetra and Royal Gramma are generally not recommended to be housed together. One of these is a marine species and the other is not; they cannot share one aquarium. Their pH ranges do not meet: Cardinal Tetra wants 4.5โ7.0 and Royal Gramma wants 8.1โ8.4. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Cardinal Tetra and Royal Gramma together?
A minimum of 20 gallons is recommended for keeping Cardinal Tetra and Royal Gramma together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Royal Gramma?
73โ82ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Royal Gramma's 72โ82ยฐF.
Is a Cardinal Tetra aggressive toward a Royal Gramma?
Cardinal Tetra is peaceful and Royal Gramma is semi. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Cardinal Tetra and Royal Gramma
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 30 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 55 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 75 gal | Best when keeping larger schools or reducing territorial pressure. |