Compatibility Overview
Guppy and Red Eye Tetra 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 29 gallons), dense planting, and close monitoring are essential.
| Factor | Guppy | Red Eye Tetra | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 72–79°F | ✅ 72–79°F |
| pH Range | 6.8–8.5 | 6.0–7.0 | ⚠️ 6.8–7.0 (narrow) |
| Temperament | peaceful | aggressive | ❌ Risk |
| Adult Size | 2.5 in | 1.6 in | ✅ Similar |
| Min. Group | 3+ | 1+ | See below |
| Min. Tank Size | 29 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Guppy — Poecilia reticulata
Hardy and colourful livebearers. Males' long flowing tails make them targets for fin-nipping species. Very prolific breeders.
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.
Frequently Asked Questions
Can Guppy live with Red Eye Tetra?
With significant caution and a larger tank. Guppy and Red Eye Tetra 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 29 gallons), dense planting, and close monitoring are essential.
What tank size do I need for Guppy and Red Eye Tetra together?
A minimum of 29 gallons is recommended for keeping Guppy and Red Eye Tetra together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Guppy and Red Eye Tetra?
72–79°F
Is a Guppy aggressive toward a Red Eye Tetra?
Guppy is peaceful and Red Eye Tetra is aggressive. Their preferred pH ranges are difficult to reconcile.
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 | 20/100 |
| Temperament | 30/100 |
| 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 | 29 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 40 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 55 gal | Best when keeping larger schools or reducing territorial pressure. |