Compatibility Overview
Ember Tetra and Koi are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
| Factor | Ember Tetra | Koi | Verdict |
|---|---|---|---|
| Temperature | 73–84°F | 50–75°F | ⚠️ 73–75°F (narrow) |
| pH Range | 5.5–7.0 | 7.0–8.5 | ⚠️ 7.0–7.0 (narrow) |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 0.8 in | 24 in | ❌ 30× difference |
| Min. Group | 8+ | 2+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Ember Tetra — Hyphessobrycon amandae
Tiny orange-red schooling tetra that is among the most adaptable nano fish. Peaceful with everything too small to eat them.
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.
Frequently Asked Questions
Can Ember Tetra live with Koi?
Generally not recommended. Ember Tetra and Koi are generally not recommended to be housed together. The issues listed above — whether water parameter incompatibility, predation risk, or aggression — create conditions where one or both fish are likely to suffer harm or chronic stress.
What tank size do I need for Ember Tetra and Koi together?
A minimum of 100 gallons is recommended for keeping Ember Tetra and Koi together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Ember Tetra and Koi?
73–75°F (narrow)
Is a Ember Tetra aggressive toward a Koi?
Ember Tetra is peaceful and Koi is peaceful. Ember Tetra requires tropical water; Koi requires cold water. These environments are incompatible.