Koi and X Ray Tetra Compatibility Overview
Koi and X Ray Tetra are generally not recommended to be housed together. Koi is a cool-water fish and X Ray Tetra is tropical, so the usable temperature range decides this pairing. The adult size gap creates a meaningful predation risk. Review the behavior and water details before deciding whether to attempt the pairing.
| Factor | Koi | X Ray Tetra | Verdict |
|---|---|---|---|
| Temperature | 50โ75ยฐF | 72โ82ยฐF | โ ๏ธ 72โ75ยฐF (narrow) |
| pH Range | 7.0โ8.5 | 6.0โ7.5 | โ ๏ธ 7.0โ7.5 (narrow) |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 24 in | 1.8 in | โ 13ร difference |
| Min. Group | 2+ | 6+ | See below |
| Min. Tank Size | 100 gallons (for both species) | โ | |
Compatibility Positives
Incompatibility Reasons
Species Profiles
Koi โ Cyprinus rubrofuscus
Large pond fish that require hundreds of gallons and cool water. Will eat any fish small enough to fit in their mouth.
X Ray Tetra โ Pristella maxillaris
The Pristella maxillaris, also known as the X-Ray Tetra, is a popular freshwater fish known for its unique appearance and peaceful nature. They are slender and iridescent, with a clear, almost x-ray-like body. They are best kept in groups of 6 or more and thrive in well-planted tanks with a moderate water flow.
Frequently Asked Questions
Can Koi live with X Ray Tetra?
Generally not recommended. Koi and X Ray Tetra are generally not recommended to be housed together. Koi is a cool-water fish and X Ray Tetra is tropical, so the usable temperature range decides this pairing. The adult size gap creates a meaningful predation risk. Review the behavior and water details before deciding whether to attempt the pairing.
What tank size do I need for Koi and X Ray Tetra together?
A minimum of 100 gallons is recommended for keeping Koi and X Ray Tetra together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Koi and X Ray Tetra?
72โ75ยฐF (narrow) โ inside Koi's 50โ75ยฐF and X Ray Tetra's 72โ82ยฐF.
Is a Koi aggressive toward a X Ray Tetra?
The adult size gap creates a meaningful predation risk.
Related Compatibility Guides
Tank Size for Koi and X Ray 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. |