Glossostigma elatinoides: the demanding show carpet
Family Phrymaceae · Australia & NZ
The bright-green competition carpet — and what it takes to keep it low.
Where it comes from
Glossostigma elatinoides is a tiny creeping plant from the wet margins of Australia and New Zealand, where it forms low mats on damp ground. In the aquarium it is one of the smallest and brightest carpeting plants available.
What to expect
It runs horizontally across the substrate, throwing up pairs of tiny bright-green paddle leaves only a few millimetres tall. Grown well it forms a dense, luminous lawn — the reason it appears in so many Nature-style competition tanks alongside Monte Carlo and dwarf hairgrass.
How to keep it
This is a high-tech plant and honest about it. Without strong light and stable CO2 it grows upward, reaching for the surface, and the carpet falls apart. It wants a rich substrate, good flow across the floor, and consistent dosing. If you cannot supply CO2, choose Monte Carlo instead.
| Parameter | Value |
|---|---|
| Lighting | High — grows tall and open without it |
| CO2 | Required for a tight carpet |
| Temperature | 20–26 °C |
| pH | 5.5–7.5 |
| Hardness | Soft to moderate |
| Fertiliser | Rich substrate; regular dosing |
| Substrate | Nutrient-rich aquasoil |
| Growth rate | Fast (given light + CO2) |
| Placement | Foreground |
| Difficulty | Advanced |
How to carpet it
Split the pot into small portions and plant them a few centimetres apart across damp aquasoil — the gaps fill in as runners spread. Many aquascapers grow it emersed (out of water) first to establish a mat before flooding. Trim the top regularly; cutting it back forces denser, lower growth.
What goes wrong
Growing tall and leggy is the classic failure and always traces back to too little light or unstable CO2. A thick carpet can also detach and float if the lower layer rots, so trim before it gets too deep. Get the light and CO2 right and it is spectacular.
More plants in this series
- Monte Carlo (Micranthemum tweediei) — the easier bright carpet
- HC Cuba (Hemianthus callitrichoides) — the tiniest carpet
- Dwarf four-leaf clover (Marsilea hirsuta) — the low-tech carpet
- Dwarf hairgrass — the grassy carpet