Compatibility Overview
Red Eye Tetra and Threadfin Rainbowfish 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 20 gallons), dense planting, and close monitoring are essential.
| Factor | Red Eye Tetra | Threadfin Rainbowfish | Verdict |
|---|---|---|---|
| Temperature | 72–79°F | 72–82°F | ✅ 72–79°F |
| pH Range | 6.0–7.0 | 6.5–7.5 | ⚠️ 6.5–7.0 (narrow) |
| Temperament | aggressive | semi | ❌ Risk |
| Adult Size | 1.6 in | 2.0 in | ✅ Similar |
| Min. Group | 1+ | 1+ | See below |
| Min. Tank Size | 20 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Red Eye Tetra — Aquarium species
The Red Eye Tetra is a popular freshwater fish known for its vibrant red eyes and sleek, silver body. They are generally peaceful and can be kept in a community tank with other non-aggressive species. Their moderate activity level makes them suitable for a variety of aquarium setups. With proper care, they can live up to 5 years.
→ Full Red Eye Tetra care guide
Threadfin Rainbowfish — Aquarium species
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. Regular water changes and a balanced diet ar
Frequently Asked Questions
Can Red Eye Tetra live with Threadfin Rainbowfish?
With significant caution and a larger tank. Red Eye Tetra and Threadfin Rainbowfish 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 20 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Red Eye Tetra and Threadfin Rainbowfish together?
A minimum of 20 gallons is recommended for keeping Red Eye Tetra and Threadfin Rainbowfish together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Red Eye Tetra and Threadfin Rainbowfish?
72–79°F
Is a Red Eye Tetra aggressive toward a Threadfin Rainbowfish?
Red Eye Tetra is aggressive and Threadfin 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 | 100/100 |
| Ph | 50/100 |
| Temperament | 25/100 |
| 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 | 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 | 40 gal | Best when keeping larger schools or reducing territorial pressure. |