Plant comparison
Guppy Grass vs Java Fern
How the Guppy Grass and Java Fern compare on care, size, water and temperament, and which plant suits your tank.
By Mike ElmiraUpdated
TL;DR, Guppy Grass vs Java Fern
The Guppy Grass and the Java Fern come up together a lot when people are choosing a plant, and they are close enough to weigh side by side. Both are happy somewhere around 20 to 28 °C and pH 6 to 7.5, 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. Read the full care notes on each below and pick the one whose look and pace fit the tank you're building.
Group compatibility overview
Excellent fit
Every key parameter overlaps and no major conflicts surfaced.
Temperature
- Guppy Grass15–28 °C
- Java Fern20–28 °C
pH
- Guppy Grass6–8
- Java Fern5.5–7.5
Hardness
- Guppy Grass3–20 dGH
- Java Fern2–15 dGH
Full attributes
Every parameter, side by side| Parameter |  PlantGuppy GrassNajas guadalupensis |  PlantJava FernMicrosorum pteropus |
|---|---|---|
| Category | Plant | Plant |
| Origin | Americas (Caribbean and Gulf) | Southeast Asia |
| Family | Hydrocharitaceae | Polypodiaceae |
| Temperature | 15–28 °C | 20–28 °C |
| pH | 6.0–8.0 | 5.5–7.5 |
| Hardness (dGH) | 3–20 | 2–15 |
| Flow rate | Low to Medium | Low to High |
| Max height | 30–60 cm | 15–35 cm |
| Difficulty | 1 / 5 | 1 / 5 |
| Light | Low to High | Low to Medium |
| CO₂ | Not required | None to Optional |
| Growth rate | Very fast | Slow |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Guppy Grass and Java Fern together?
Yes. Their temperature and pH ranges overlap around 20 to 28 °C and pH 6 to 7.5, 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 Grass or the Java Fern?
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 Guppy Grass and Java Fern need the same water?
Close to it. Aim for 20 to 28 °C and pH 6 to 7.5 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 Grass and the Java Fern?
Placement and light. The Guppy Grass works as background or floating, the Java Fern as midground or background, and their light needs differ, which is covered in the table.