Greater duckweed: a water-purifying floating plant that provides natural shade
For a light-filtering surface, a duckweed that stands out
Greater duckweed (Spirodela polyrhiza) is a rare, attractive floating plant that is larger and easier to control than common duckweed (Lemna minor). It quickly forms a plant cover on the surface, limiting algae growth by absorbing nitrates and phosphates. It also creates shade, reduces evaporation and provides shelter for microfauna and fry.
Its size (3 to 10 mm per leaf) makes it harder for goldfish to eat (except the largest ones), but koi enjoy it.
Why add Greater Duckweed to an aquarium or pond?
- Absorbs nitrates and phosphates → naturally helps control algae and purify the water
- Provides shelter for microfauna among its short roots: fry hide there and find live infusoria
- Easy to control: its leaves are larger and therefore easier to scoop out than common duckweed
- Suitable for ponds, outdoor tub aquariums and low-tech aquariums
- Reduces evaporation outdoors and provides some cooling shade during heat waves
Growing and care tips
- 🌿 Floating plant: no substrate or fertilizer needed, as it gets all its nutrients from the water
- 💨 CO2 is completely unnecessary, since it absorbs it from the air, not the water
- ❄️ Cold-tolerant: can overwinter outdoors because it produces dormant forms (take a few plants to get a head start in spring)
- 🌞 Sadapts to both direct and filtered light
- ✂️ Regularly remove excess plants to let light reach submerged plants
- 🐟 Compatible with fish, snails (for example, bladder snails), daphnia, water lice, and aquatic microfauna
FAQ - Greater duckweed
Does this duckweed take over everything?
It often spreads quickly, but the larger leaves are much easier to remove by hand.
Can it be placed in a small aquarium?
Yes, it adapts well to nano tanks, provided its growth is kept in check. Keep just a few plants to provide light, uneven shading.
Compatible with goldfish?
Yes, they will eat very little of it (except the biggest ones!). Larger carp, on the other hand, enjoy it very much.
Does it really protect fry?
Yes, its 2 cm roots grow in clusters, and its leaves provide a reassuring shelter for young fish. Above all, though, they find live infusoria there.
Is it a true filtering plant?
Yes, it absorbs excess nitrates and phosphates, helping maintain 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 plant that purifies and filters water
Packaging: set of 30 plants (indicative weight: 5 g)
Guarantee: plants grown without any artificial inputs. No fertilizers, algaecides, or antibiotics.
