Guppy and Molly Compatibility Overview
Short answer: Yes. Both do well at 72-82°F and both are peaceful. Match the tank size and group size in the table below and both should do well.
Guppy and Molly 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 | 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. 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 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 — inside Guppy's 72–82°F and Molly's 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.
More Good Tank Mates for Guppy and Molly
The highest-scoring compatible partners for each species in our compatibility data.
For Guppy
- Neon Rainbowfish — 96/100
- Clown Pleco — 95/100
- Pearl Danio — 93/100
- Zebra Danio — 93/100
- Mystery Snail — 92/100
For Molly
- Platy — 92/100
- Swordtail — 89/100
- Electric Yellow Cichlid — 88/100
- Peacock Cichlid — 87/100
- Corydoras — 86/100
Related Compatibility Guides
Tank Size for Guppy and Molly
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. |