Compatibility Overview
Discus and Oscar 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 | Discus | Oscar | Verdict |
|---|---|---|---|
| Temperature | 82–88°F | 74–81°F | ❌ No overlap |
| pH Range | 5.0–7.0 | 6.0–8.0 | ✅ 6.0–7.0 |
| Temperament | semi | aggressive | ❌ Risk |
| Adult Size | 8 in | 14 in | ✅ Similar |
| Min. Group | 5+ | 1+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
❌ Incompatibility Reasons
Species Profiles
Discus — Symphysodon spp.
The 'king of the aquarium' — beautiful but demanding. Requires very warm, soft, acidic water that excludes most community fish.
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.
Frequently Asked Questions
Can Discus live with Oscar?
Generally not recommended. Discus and Oscar 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 Discus and Oscar together?
A minimum of 100 gallons is recommended for keeping Discus and Oscar together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Discus and Oscar?
No overlap
Is a Discus aggressive toward a Oscar?
Discus is semi and Oscar is aggressive. Temperature ranges do not overlap: Discus needs 82–88°F; Oscar needs 74–81°F.