Compatibility Overview
Cardinal Tetra and Neon Rainbowfish can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 40-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Cardinal Tetra | Neon Rainbowfish | Verdict |
|---|---|---|---|
| Temperature | 73–82°F | 72–79°F | ✅ 73–79°F |
| pH Range | 4.5–7.0 | 6.5–7.5 | ⚠️ 6.5–7.0 (narrow) |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 1.5 in | 1.6 in | ✅ Similar |
| Min. Group | 6+ | 1+ | See below |
| Min. Tank Size | 40 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Cardinal Tetra — Paracheirodon axelrodi
Brilliant red-and-blue schooling fish from the Rio Negro. Prefers soft, acidic, warm water — a natural companion for discus.
→ Full Cardinal Tetra care guide
Neon Rainbowfish — Aquarium species
The Neon Rainbowfish, known for its vibrant colors, is a popular addition to freshwater aquariums. These fish are generally peaceful and can be kept in community tanks with other peaceful species. They require a well-maintained tank with a good water flow and plenty of swimming space. Regular water changes and a balanced diet are essential for their health.
Frequently Asked Questions
Can Cardinal Tetra live with Neon Rainbowfish?
Yes, in a well-planned setup. Cardinal Tetra and Neon Rainbowfish can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 40-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Cardinal Tetra and Neon Rainbowfish together?
A minimum of 40 gallons is recommended for keeping Cardinal Tetra and Neon Rainbowfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Neon Rainbowfish?
73–79°F
Is a Cardinal Tetra aggressive toward a Neon Rainbowfish?
Cardinal Tetra is peaceful and Neon Rainbowfish is semi. No major aggression issues are expected between these species.
Related Compatibility Guides
Compatibility score breakdown
The overall score is weighted across water chemistry, behavior, adult size, swimming zone, and social needs. A score is a planning aid—not a guarantee for individual fish.
| Factor | Score |
|---|---|
| Temperature | 86/100 |
| Ph | 50/100 |
| Temperament | 75/100 |
| Adult Size | 100/100 |
| Swim Zone | 68/100 |
| Social Needs | 92/100 |
Tank size scenarios
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 40 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 | 90 gal | Best when keeping larger schools or reducing territorial pressure. |