Duckweed (Lemna minor) - Portion Cup

Duckweed (Lemna minor) is a tiny, free-floating plant that forms a soft green blanket across the water's surface. It is one of the fastest-growing plants in the hobby, making it a powerful natural filter that pulls excess nitrate and phosphate out of the water and starves out algae. It also provides shade, dampens surface agitation, and is a favorite live food for goldfish, cichlids, and turtles. Each portion cup gives you a healthy starter colony.

Browse the rest of our live aquarium plants to round out your tank.

Grows Fast, Read This First

Duckweed multiplies quickly and can cover the entire surface in a week or two under good conditions. That is exactly what you want for nutrient export and as a food source, but plan to scoop out the excess regularly to keep the surface where you want it. Because it spreads so readily, it is best added intentionally and is hard to fully remove once established.

Care Guide

• Care level: Very easy
• Lighting: Low to high; brighter light means faster spread
• Placement: Floating on the surface
• Growth: Very fast; skim off excess regularly to control coverage
• CO2: Not required
• Flow: Prefers calm water; strong surface agitation pushes it to the edges
• Propagation: Splits and multiplies on its own, no effort needed

Specifications

Best Uses & Other Floaters

Duckweed is great for nutrient export, fry cover, and as live food. If you want floating plants with a different look, try:

• Red Root Floater for red-tinged surface color
• Frogbit for larger, lily-pad-like leaves
• Water Lettuce for a bold rosette and long trailing roots

FAQ

Will duckweed take over my tank?
It can. Under good light it doubles fast and will cover the surface, which is why it is such an effective nutrient sponge. Skim off the excess every week or two to keep it in check.

Is duckweed good or bad?
Both, depending on your goal. It is fantastic for absorbing nutrients, shading the tank, sheltering fry, and feeding herbivorous fish. The trade-off is regular maintenance to control its spread.

Can I feed it to my fish?
Yes. Goldfish, many cichlids, and turtles love duckweed as a fresh, nutritious live food.

Does it need CO2 or fertilizer?
No. As a floating plant it pulls CO2 from the air and feeds heavily on tank nutrients, so it thrives with no extra inputs.