Molly and Swordtail Compatibility Overview
Molly and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Both species are peaceful, and neither poses a major aggression risk to the other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Molly | Swordtail | Verdict |
|---|---|---|---|
| Temperature | 72โ82ยฐF | 65โ80ยฐF | โ 72โ80ยฐF |
| pH Range | 7.5โ8.5 | 7.0โ8.3 | โ 7.5โ8.3 |
| Temperament | peaceful | peaceful | โ Compatible |
| Adult Size | 4 in | 5 in | โ Similar |
| Min. Group | 3+ | 3+ | See below |
| Min. Tank Size | 55 gallons (for both species) | โ | |
Compatibility Positives
Caution Points
Species Profiles
Molly โ Poecilia sphenops
Hardy livebearers that prefer alkaline, hard water โ sometimes slightly brackish. Prolific breeders; peaceful community fish.
Swordtail โ 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 Molly live with Swordtail?
Yes, in a well-planned setup. Molly and Swordtail can generally share an aquarium with appropriate planning. Both species prefer overlapping temperature and pH ranges. Both species are peaceful, and neither poses a major aggression risk to the other. A minimum 55-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Molly and Swordtail together?
A minimum of 55 gallons is recommended for keeping Molly and Swordtail together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Molly and Swordtail?
72โ80ยฐF โ inside Molly's 72โ82ยฐF and Swordtail's 65โ80ยฐF.
Is a Molly aggressive toward a Swordtail?
Molly is peaceful and Swordtail is peaceful. No major aggression issues are expected between these species.
Related Compatibility Guides
Tank Size for Molly and Swordtail
Use the scenario that matches the actual group sizes and temperament you plan to keep.
| Scenario | Tank | When it applies |
|---|---|---|
| Minimum viable | 55 gal | Only for the recommended minimum groups, mature filtration, and close monitoring. |
| Recommended community | 75 gal | Adds territory, swimming room, and a safer buffer for behavior. |
| Low-conflict setup | 125 gal | Best when keeping larger schools or reducing territorial pressure. |