Dwarf Water Lettuce
Dwarf water lettuce floats like little velvety green rosettes of romaine, trailing thick roots that shade and clean the water - a favourite of aquascapers and shrimp keepers.
🗓️ Last reviewed: July 2026
Overview
Dwarf water lettuce floats like little velvety green rosettes of romaine, trailing thick roots that shade and clean the water - a favourite of aquascapers and shrimp keepers. But the same fast growth makes it a serious invasive; it is banned in several US states, so check your local rules and never release it. (Pistia stratiotes.)
Origin & Natural Habitat
Debated tropical origin; now found - and often invasive - in warm still waters worldwide.
Appearance
Ribbed, fuzzy pale-green leaves in a rose shape floating on the surface, with dense feathery roots hanging below.
Why People Grow It - Qualities & Benefits
- Fast nutrient export and shade
- Beautiful trailing roots for shrimp/fry
- No substrate needed
- Softens hard light
Care
Light: Moderate to high from above.
Water: 20-30°C, pH 6.5-7.5; loves warm water.
Substrate: None - floats; feeds from the water column.
CO₂ & feeding: Not needed.
Placement: Surface, corralled so it does not carpet the whole top.
Extra: ⚠️ Water lettuce is a listed invasive/noxious weed in a number of US states (and other regions) - it is illegal to keep or move in some. Check your local rules before buying, keep it contained, and dispose of it dry in the bin. Never put it in a pond, ditch or waterway.
Propagation
Rapid daughter rosettes; thin constantly to control it.
Common Problems & Pests
Melts if the leaves get splashed or the air is too dry; overgrows the surface; legal restrictions. Needs warmth and humidity under the lid.
Toxicity & Safety
Non-toxic to fish and shrimp, but a major invasive - dispose of it sealed and dry, never release it. Confirm it is legal where you live.
Best Suited For
- Shrimp and fry tanks (where legal)
- Warm, humid, covered tanks
- Nutrient export
- NOT for release or unrestricted keeping
FAQ
Is water lettuce legal to own?
It depends on where you live - it is a banned noxious weed in several US states and other regions because it is highly invasive. Check local regulations first, and never release it.
Why does mine keep melting?
It wants warmth and humid air above the surface, and hates splashed leaves. Keep a lid, a small air gap, and a calm surface.