Compatibility Overview
Guppy and Molly 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 55-gallon tank is recommended to provide adequate territory and water volume for both species.
| Factor | Guppy | Molly | Verdict |
|---|---|---|---|
| Temperature | 72–82°F | 72–82°F | ✅ 72–82°F |
| pH Range | 6.8–8.5 | 7.5–8.5 | ✅ 7.5–8.5 |
| Temperament | peaceful | peaceful | ✅ Compatible |
| Adult Size | 2.5 in | 4 in | ✅ Similar |
| Min. Group | 3+ | 3+ | See below |
| Min. Tank Size | 55 gallons (for both species) | — | |
✅ Compatibility Positives
⚠️ Caution Points
Species Profiles
Guppy — Poecilia reticulata
Hardy and colourful livebearers. Males' long flowing tails make them targets for fin-nipping species. Very prolific breeders.
Molly — Poecilia sphenops
Hardy livebearers that prefer alkaline, hard water — sometimes slightly brackish. Prolific breeders; peaceful community fish.
Frequently Asked Questions
Can Guppy live with Molly?
Yes, in a well-planned setup. Guppy and Molly 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 55-gallon tank is recommended to provide adequate territory and water volume for both species.
What tank size do I need for Guppy and Molly together?
A minimum of 55 gallons is recommended for keeping Guppy and Molly together. A larger tank improves water stability and reduces territorial conflict.
What temperature suits both Guppy and Molly?
72–82°F
Is a Guppy aggressive toward a Molly?
Guppy is peaceful and Molly is peaceful. No major aggression issues are expected between these species.