Compatibility Overview
Cardinal Tetra and Glowlight Danio can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 40 gallons), dense planting, and close monitoring are essential.
| Factor | Cardinal Tetra | Glowlight Danio | Verdict |
|---|---|---|---|
| Temperature | 73–82°F | 72–82°F | ✅ 73–82°F |
| pH Range | 4.5–7.0 | 6.0–7.5 | ✅ 6.0–7.0 |
| Temperament | peaceful | aggressive | ❌ Risk |
| Adult Size | 1.5 in | 1.6 in | ✅ Similar |
| Min. Group | 6+ | 6+ | 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
Glowlight Danio — Aquarium species
The Glowlight Danio is a popular freshwater fish known for its vibrant colors and active nature. They are ideal for beginners due to their hardiness and ease of care. These fish thrive in a well-maintained tank with plenty of swimming space and a school of their own kind.
Frequently Asked Questions
Can Cardinal Tetra live with Glowlight Danio?
With significant caution and a larger tank. Cardinal Tetra and Glowlight Danio can potentially coexist, but the combination requires careful attention. Some combination of water parameter differences, size mismatch, or temperament issues make this pair challenging. A larger tank (minimum 40 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Cardinal Tetra and Glowlight Danio together?
A minimum of 40 gallons is recommended for keeping Cardinal Tetra and Glowlight Danio together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Cardinal Tetra and Glowlight Danio?
73–82°F
Is a Cardinal Tetra aggressive toward a Glowlight Danio?
Cardinal Tetra is peaceful and Glowlight Danio is aggressive. 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 | 100/100 |
| Ph | 67/100 |
| Temperament | 30/100 |
| Adult Size | 100/100 |
| Swim Zone | 68/100 |
| Social Needs | 85/100 |
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. |