Greater duckweed: purifying floating plant and natural shade
For a surface that filters light, a duckweed that stands out
Greater duckweed (Spirodela polyrhiza) is a rare and attractive floating plant, larger and easier to manage than common duckweed (Lemna minor). It quickly forms a vegetative mat on the surface, limiting algae proliferation by absorbing nitrates and phosphates. It also creates shade, reduces evaporation, and serves as a refuge for microfauna and fry.
Its size (3 to 10 mm per leaf) makes it less easy to eat for goldfish (except the largest), but it is appreciated by carps.
Why introduce Greater duckweed into an aquarium or pond?
- Absorbs nitrates and phosphates → natural algae control and water purification
- Provides shelter for microfauna in its short roots: fry take refuge there and find living infusoria
- Easy control: larger leaves and therefore easier to collect than the common duckweed
- Compatible with ponds, trashcan aquariums, and low-tech aquariums
- Limits evaporation outdoors and preserves some coolness during heatwaves by providing shade
Cultivation and maintenance tips
- 🌿 Floating plant: no substrate or fertilizer needed, it feeds exclusively in the water
- 💨 CO2 completely unnecessary, since it takes it from the air and not from the water
- ❄️ Tolerates cold: winter possible outdoors as it produces dormant forms (take some plants to restart earlier in spring)
- 🌞 Adapts to direct or filtered light
- ✂️ Regularly remove the excess to let light pass to submerged plants
- 🐟 Compatible with fish, snails (bladder snails for example), daphnia, water lice and aquatic microfauna
FAQ - Greater duckweed
Does this duckweed take over everything?
Its propagation is often rapid, but the larger leaves are much easier to remove by hand.
Can it be put in a small aquarium?
Yes, it adapts well to nano tanks, provided its growth is regulated. Keep only a few plants to obtain a light and irregular screening of the light.
Compatible with goldfish?
Yes, they will consume it little (except the bigger ones!). Large carp, on the other hand, appreciate it a lot.
Does it really protect fry?
Yes, its 2 cm roots in clusters and its leaves provide a reassuring shelter for young fish. But above all, they find living infusoria there.
Is it a true filtering plant?
Yes, it captures excess nitrates and phosphates, contributing to the biological balance of the water. It is more accurate to speak of purification than filtration.
Additional information
Scientific name: Spirodela polyrhiza
Plant type: floating purifying and screening plant
Packaging: batch of 30 plants (indicative weight: 5 g)
Guarantee: plants grown without any artificial input. No fertilizer, no algaecide, no antibiotic.
