Duckweed (Lemna Minor)

Duckweed (Lemna Minor)

Duckweed is one of the fastest-growing and most adaptable floating plants in the hobby. It’s excellent for soaking up excess nutrients, providing natural shade, and creating a more “pond-like” feel in both aquariums and outdoor tubs.

Duckweed Overview

Lemna minor, commonly known as duckweed, is a hardy, easy-going floating plant that produces tiny, oval leaves (fronds) measuring only a few millimeters across. We ship our duckweed in a 4 oz container or by the pound, giving you plenty of plant mass to get started.

On the water’s surface, duckweed forms a soft, clover-like mat of light green leaves. Delicate, root-like structures hang beneath each frond, swaying gently in the current. In an aquarium, this floating canopy:

• Softens overhead lighting and creates natural shade
• Helps shy fish, small fish, and fry feel more secure near the surface
• Provides a habitat where fry and micro-organisms can thrive
• Adds a simple but attractive “natural pond” look to open-top tanks and tubs

Duckweed reproduces rapidly through vegetative reproduction—each frond can produce new fronds that quickly spread across the surface. Under good conditions, a small starter portion can cover the surface of an average aquarium within a week.

Many fish, especially goldfish and koi, enjoy grazing on duckweed, and other species will appreciate the shade and cover it provides. Because of its fast growth and nutrient uptake, duckweed is particularly useful in tanks or tubs with a heavy biological load, where it helps absorb excess nutrients from the water column and can assist in keeping algae in check.

Caring for Duckweed

Duckweed is very easy to care for and thrives in a wide range of conditions. It does not require strong light, special substrate, or CO₂. However, because it grows quickly, some simple maintenance will keep it from taking over your tank.

• Light: Moderate
• Temperature Range: 41–95°F
• Placement: Floating
• CO₂: Not required
• Difficulty: Easy
• Growth Rate: Very fast

To manage duckweed, simply remove excess fronds during regular maintenance with a net or cup, leaving as much or as little coverage as you prefer. Keeping part of the surface open ensures good gas exchange and allows light to reach plants below. Duckweed can be used in a wide variety of setups—from temperate tanks and outdoor tubs to tropical community aquariums—thanks to the broad temperature range in which it thrives.

Duckweed also pairs nicely with other floating plants such as Water Lettuce and Red Root Floater, allowing you to create layered surface cover with different shapes, colors, and root structures.

Plants From Modern Aquarium

The Duckweed offered by Modern Aquarium is portioned generously and selected for freshness and vigor, so it can establish quickly and start providing shade and nutrient export in your tank.

• Top Quality Store: Modern Aquarium has been designated by Google as a Top Quality Store and has over 2,000 individual verified reviews from real customers, so you can shop with confidence.
• Live Arrival Guarantee & Fast Shipping: All of our live plants are covered by our Live Arrival Guarantee and are shipped via FedEx 2-Day delivery to help ensure they reach you healthy, fresh, and ready to thrive.
• Trusted Sourcing: Our plants are sourced from some of the best nurseries in Florida and are handled with care from the grower to your aquarium.
• What You See Is What You Get: Every image on our site is a typical representation of the plants we sell—no unrealistic stock photos. Because live plants are natural products, individual portions will vary in density and appearance.
• Helpful Customer Service: If you have questions about how much duckweed to use, how to control its growth, or which plants and snails pair well with it, our customer service team is happy to help with practical, hobby-focused advice.

For a complete setup, combine Duckweed with other live aquarium plants from our collection and accent your layout with our natural driftwood, aquascaping rocks, and botanicals. To help keep glass and hardscape free of algae while staying plant-safe, consider adding our Tiger Eye Nerite Snails, exceptional algae eaters that will not reproduce in freshwater—an ideal complement to a thriving, duckweed-covered planted tank.