Fish comparison
Guppy vs Sailfin Molly
How the Guppy and Sailfin Molly compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Guppy vs Sailfin Molly
The Guppy and the Sailfin Molly are close cousins, both in the Poecilia group, so at a glance they ask for a lot of the same things. Both are happy somewhere around 22 to 28 °C and pH 7.5 to 8, so a single tank can suit either one. The Guppy is the more forgiving of the two, which matters if this is an early tank, while the Sailfin Molly rewards a bit more attention. If tank space is tight, the Guppy needs less room to feel settled; give the Sailfin Molly the nod when you have the litres to spare.
Group compatibility overview
Excellent fit
Every key parameter overlaps and no major conflicts surfaced.
1 note
Temperature
- Guppy22–28 °C
- Sailfin Molly22–28 °C
pH
- Guppy6.8–8
- Sailfin Molly7.5–8.5
Hardness
- Guppy8–25 dGH
- Sailfin Molly15–30 dGH
What to plan for
- No bottom teamNo bottom-dwelling fish or shrimp. A small group of corydoras or a shrimp colony picks up leftover food and keeps detritus in check.
Full attributes
Every parameter, side by side| Parameter |  FishGuppyPoecilia reticulata |  FishSailfin MollyPoecilia latipinna |
|---|---|---|
| Category | Fish | Fish |
| Origin | Northeastern South America, naturalised globally | Southeastern USA & Mexico, some brackish populations |
| Family | Poeciliidae | Poeciliidae |
| Temperature | 22–28 °C | 22–28 °C |
| pH | 6.8–8.0 | 7.5–8.5 |
| Hardness (dGH) | 8–25 | 15–30 |
| Flow rate | Low to Medium | Low to Medium |
| Min tank | 45 L | 120 L |
| Adult size | 3–6 cm | 8–12 cm |
| Difficulty | 1 / 5 | 2 / 5 |
| Lifespan | 1–2 yrs | 3–5 yrs |
| Diet | Omnivore | Omnivore (heavy plant matter) |
| Water column | Mid to Top | Mid to Top |
| Schooling | No (live in groups) | No (live in groups) |
| Plant safe | Yes | Mostly (may nip soft leaves) |
| Shrimp safe | Yes (with adults; may eat shrimplets) | Adults only (will eat shrimplets) |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Guppy and Sailfin Molly together?
Yes. Their temperature and pH ranges overlap around 22 to 28 °C and pH 7.5 to 8, so one set of water conditions keeps both comfortable. Match group sizes and cover the usual planted-tank basics and they share a tank fine.
Which is easier to keep, the Guppy or the Sailfin Molly?
The Guppy is the easier of the two, closer to very easy, while the Sailfin Molly leans beginner-friendly.
Do Guppy and Sailfin Molly need the same water?
Close to it. Aim for 22 to 28 °C and pH 7.5 to 8 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Guppy and the Sailfin Molly?
Space. The Guppy wants about 45 litres minimum and the Sailfin Molly around 120, so tank size can settle it.