Compatibility Overview
Corydoras Catfish 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 | Corydoras Catfish | Koi | Verdict |
|---|---|---|---|
| Temperature | 70–79°F | 50–75°F | ✅ 70–75°F |
| pH Range | 6.0–8.0 | 7.0–8.5 | ✅ 7.0–8.0 |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 2.5 in | 24 in | ❌ 10× difference |
| Min. Group | 6+ | 2+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Corydoras Catfish — Corydoras spp.
Armoured bottom-dwelling catfish that are peaceful with all non-aggressive species. Need fine sand substrate to protect delicate barbels.
→ Full Corydoras Catfish care guide
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 Corydoras Catfish live with Koi?
Generally not recommended. Corydoras Catfish 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 Corydoras Catfish and Koi together?
A minimum of 100 gallons is recommended for keeping Corydoras Catfish and Koi together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Corydoras Catfish and Koi?
70–75°F
Is a Corydoras Catfish aggressive toward a Koi?
Corydoras Catfish is peaceful and Koi is peaceful. Corydoras Catfish requires tropical water; Koi requires cold water. These environments are incompatible.