Compatibility Overview
Oscar and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 100-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Oscar | Swordtail | Verdict |
|---|---|---|---|
| Temperature | 74–81°F | 65–80°F | ✅ 74–80°F |
| pH Range | 6.0–8.0 | 7.0–8.3 | ✅ 7.0–8.0 |
| Temperament | aggressive | peaceful | ❌ Risk |
| Adult Size | 14 in | 5 in | ⚠️ 2.8× difference |
| Min. Group | 1+ | 3+ | See below |
| Min. Tank Size | 100 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
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.
Swordtail — Xiphophorus hellerii
Hardy livebearer with a distinctive elongated lower tail fin in males. Peaceful community fish that tolerate a wide temperature range.
Frequently Asked Questions
Can Oscar live with Swordtail?
Yes, in a well-planned setup. Oscar and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges, and neither poses a major aggression risk to the other. A minimum 100-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Oscar and Swordtail together?
A minimum of 100 gallons is recommended for keeping Oscar and Swordtail together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Oscar and Swordtail?
74–80°F
Is a Oscar aggressive toward a Swordtail?
Oscar is aggressive and Swordtail is peaceful. No major aggression issues are expected between these species.