Koi and Neon Tetra Compatibility Overview
Short answer: No. Koi needs 50-75°F and Neon Tetra needs 72-80°F. Keep them in separate tanks, or pick one of the safer tank mates listed below.
Koi and Neon Tetra are generally not recommended to be housed together. Koi is a cool-water fish and Neon Tetra is tropical, so the usable temperature range decides this pairing. Koi will eat neon tetras. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Koi | Neon Tetra | Verdict |
|---|---|---|---|
| Temperature | 50–75°F | 72–80°F | ⚠️ 72–75°F (narrow) |
| pH Range | 7.0–8.5 | 6.0–7.5 | ⚠️ 7.0–7.5 (narrow) |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 24 in | 1.5 in | ❌ 16× difference |
| Min. Group | 2+ | 6+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Koi — Cyprinus rubrofuscus
Large pond fish that require hundreds of gallons and cool water. Will eat any fish small enough to fit in their mouth.
Neon Tetra — Paracheirodon innesi
Iconic schooling fish with vivid electric-blue and red stripes. Hardy in captivity; suitable for most peaceful community setups.
Frequently Asked Questions
Can Koi live with Neon Tetra?
Generally not recommended. Koi and Neon Tetra are generally not recommended to be housed together. Koi is a cool-water fish and Neon Tetra is tropical, so the usable temperature range decides this pairing. Koi will eat neon tetras. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Koi and Neon Tetra together?
A minimum of 100 gallons is recommended for keeping Koi and Neon Tetra together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Koi and Neon Tetra?
72–75°F (narrow) — inside Koi's 50–75°F and Neon Tetra's 72–80°F.
Is a Koi aggressive toward a Neon Tetra?
The adult size gap creates a meaningful predation risk.
Safer Tank Mates for Koi and Neon Tetra
The highest-scoring compatible partners for each species in our compatibility data.
For Koi
- Weather Loach — 87/100
- Goldfish — 86/100
For Neon Tetra
- Dwarf Chain Loach — 98/100
- Panda Cory — 98/100
- Pearl Danio — 98/100
- Peppered Cory — 98/100
- Pygmy Corydoras — 98/100
Related Compatibility Guides
Tank Size for Koi and Neon Tetra
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 100 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 150 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 220 gal | Best when keeping larger schools or reducing territorial pressure. |