Compatibility Overview
Oscar and Pygmy Corydoras 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 | Oscar | Pygmy Corydoras | Verdict |
|---|---|---|---|
| Temperature | 74–81°F | 72–79°F | ✅ 74–79°F |
| pH Range | 6.0–8.0 | 6.0–7.5 | ✅ 6.0–7.5 |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 14 in | 1 in | ❌ 14× difference |
| Min. Group | 1+ | 6+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Oscar — Astronotus ocellatus
Intelligent but aggressive cichlids that will eat any fish small enough to fit in their mouth. Require large tanks (75+ gallons) and robust tank mates.
Pygmy Corydoras — Corydoras pygmaeus
Tiny armoured catfish that school in open water as well as on the substrate. Peaceful with all non-aggressive species.
Frequently Asked Questions
Can Oscar live with Pygmy Corydoras?
Generally not recommended. Oscar and Pygmy Corydoras 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 Oscar and Pygmy Corydoras together?
A minimum of 100 gallons is recommended for keeping Oscar and Pygmy Corydoras together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Oscar and Pygmy Corydoras?
74–79°F
Is a Oscar aggressive toward a Pygmy Corydoras?
Oscar is aggressive and Pygmy Corydoras is peaceful. Oscars will eat pygmy corydoras.