Compatibility Overview
Koi and Yoyo Loach 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 | Koi | Yoyo Loach | Verdict |
|---|---|---|---|
| Temperature | 50–75°F | 72–79°F | ⚠️ 72–75°F (narrow) |
| pH Range | 7.0–8.5 | 6.5–7.5 | ⚠️ 7.0–7.5 (narrow) |
| Temperament | peaceful | semi | ⚠️ Monitor |
| Adult Size | 24 in | 2.0 in | ❌ 12× difference |
| Min. Group | 2+ | 1+ | 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.
Yoyo Loach — Aquarium species
The Yoyo Loach is a popular freshwater species known for its striking black and white coloration. They are peaceful and make great community fish, though they may be shy and require a well-established tank with ample hiding spots. These loaches are moderately active and do well in a tank with plenty of room to swim. With proper care, they can live up to 5 ye
Frequently Asked Questions
Can Koi live with Yoyo Loach?
Generally not recommended. Koi and Yoyo Loach 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 Koi and Yoyo Loach together?
A minimum of 100 gallons is recommended for keeping Koi and Yoyo Loach together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Koi and Yoyo Loach?
72–75°F (narrow)
Is a Koi aggressive toward a Yoyo Loach?
Koi is peaceful and Yoyo Loach is semi. These animals require different water types and cannot share one aquarium.
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 | 43/100 |
| Ph | 50/100 |
| Temperament | 75/100 |
| Adult Size | 8/100 |
| Swim Zone | 92/100 |
| 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 | 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 | 180 gal | Best when keeping larger schools or reducing territorial pressure. |