Fish comparison
Southern Platy vs Green Swordtail
How the Southern Platy and Green Swordtail compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Southern Platy vs Green Swordtail
The Southern Platy and the Green Swordtail are close cousins, both in the Xiphophorus group, so at a glance they ask for a lot of the same things. Both are happy somewhere around 22 to 26 °C and pH 7 to 8.2, so a single tank can suit either one. Neither is harder than the other to keep, so the choice comes down to look and stocking rather than skill. If tank space is tight, the Southern Platy needs less room to feel settled; give the Green Swordtail 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
- Southern Platy20–26 °C
- Green Swordtail22–28 °C
pH
- Southern Platy7–8.2
- Green Swordtail7–8.4
Hardness
- Southern Platy10–25 dGH
- Green Swordtail12–30 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 |  FishSouthern PlatyXiphophorus maculatus |  FishGreen SwordtailXiphophorus hellerii |
|---|---|---|
| Category | Fish | Fish |
| Origin | Mexico and Central America | Central America (southern Mexico to Honduras) |
| Family | Poeciliidae | Poeciliidae |
| Temperature | 20–26 °C | 22–28 °C |
| pH | 7.0–8.2 | 7.0–8.4 |
| Hardness (dGH) | 10–25 | 12–30 |
| Flow rate | Low to Medium | Low to Medium |
| Min tank | 60 L | 100 L |
| Adult size | 4–6 cm | 10–14 cm (males include sword) |
| Difficulty | 1 / 5 | 1 / 5 |
| Lifespan | 3–5 yrs | 3–5 yrs |
| Diet | Omnivore | Omnivore |
| Water column | Mid to Top | Mid to Top |
| Schooling | No (live in groups) | No (live in groups) |
| Plant safe | Yes | Mostly (may nip) |
| Shrimp safe | Yes (with adults; may eat shrimplets) | Adults only |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Southern Platy and Green Swordtail together?
Yes. Their temperature and pH ranges overlap around 22 to 26 °C and pH 7 to 8.2, 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 Southern Platy or the Green Swordtail?
They sit at the same care level, both very easy, so neither is the obvious beginner pick. The decision is really about the look you're after.
Do Southern Platy and Green Swordtail need the same water?
Close to it. Aim for 22 to 26 °C and pH 7 to 8.2 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Southern Platy and the Green Swordtail?
Space. The Southern Platy wants about 60 litres minimum and the Green Swordtail around 100, so tank size can settle it.