Cardinal Tetra and Rainbow Shark Compatibility Overview
Cardinal Tetra and Rainbow Shark can potentially coexist, but the combination requires careful attention. Their pH ranges overlap only partly, so aim for the shared band and keep it steady. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
| Factor | Cardinal Tetra | Rainbow Shark | Verdict |
|---|---|---|---|
| Temperature | 73โ82ยฐF | 72โ79ยฐF | โ 73โ79ยฐF |
| pH Range | 4.5โ7.0 | 6.5โ7.5 | โ ๏ธ 6.5โ7.0 (narrow) |
| Temperament | peaceful | semi | โ ๏ธ Monitor |
| Adult Size | 1.5 in | 6 in | โ 4ร difference |
| Min. Group | 6+ | 1+ | 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
Rainbow Shark โ Epalzeorhynchos frenatum
Active bottom dweller that becomes territorial at maturity. One per tank; avoid other shark-like or bottom-dwelling species.
Frequently Asked Questions
Can Cardinal Tetra live with Rainbow Shark?
With significant caution and a larger tank. Cardinal Tetra and Rainbow Shark can potentially coexist, but the combination requires careful attention. Their pH ranges overlap only partly, so aim for the shared band and keep it steady. A larger tank (minimum 75 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Cardinal Tetra and Rainbow Shark together?
A minimum of 75 gallons is recommended for keeping Cardinal Tetra and Rainbow Shark together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Rainbow Shark?
73โ79ยฐF โ inside Cardinal Tetra's 73โ82ยฐF and Rainbow Shark's 72โ79ยฐF.
Is a Cardinal Tetra aggressive toward a Rainbow Shark?
Cardinal Tetra is peaceful and Rainbow Shark is semi. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Cardinal Tetra and Rainbow Shark
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. |