PlantLab › Plants › Duckweed

Floating · Beginner friendly

Duckweed

Lemna minor

1 / 2

✦ DIFFICULTY Easy

A forgiving choice for newer planted tanks.

☀ LIGHT Moderate

Around 9 hours is a useful starting point.

≈ CO₂ Optional

Injection is not normally necessary.

↗ GROWTH Fast

Weekly trimming needs.

PLANT OVERVIEW

About Duckweed

A tiny, fast-spreading surface floater and nutrient sponge.

Duckweed is a minuscule floating plant that multiplies explosively, shading the tank and soaking up nutrients — great for absorbing excess nitrate and giving fry cover, but nearly impossible to eradicate once established. Many keepers add it deliberately; others consider it a weed.

Shrimp friendly Low-tech suitable High-tech suitable Fry cover

CARE PROFILE

What this plant needs.

The useful numbers and practical notes, grouped around how you actually keep the plant.

□

TANK FIT

Placement + size

Primary placementFloating

Typical height0–1 in

Typical width1 in

Suggested minimum tank5 gal

Suggested tank height6 in+

☀

LIGHT + CO₂

Energy demand

Ideal lightModerate

Photoperiod range8–11 hr

Approx. PAR20–55

Injected CO₂Optional

CO₂ benefitVery Low

●

NUTRITION

Where it feeds

Root feedingVery Low

Water-column feedingHigh

Overall fertilizer demandModerate

Iron demandHigh

MicronutrientsModerate

≈

WATER

Useful parameter range

Temperature68–84°F

pH6–7.8

GH2–15 dGH

KH1–12 dKH

PLANTING

How to plant it.

Substrate: None — floats at the surface

Leave floating; keep the surface calm and avoid trapping leaves under filter output.

GROWTH + PROPAGATION

What to expect after planting.

Propagation

Division / daughter plants

Acclimation

Sensitive to condensation and heat on the leaf tops; keep a gap under lids.

COMMON PROBLEMS

What usually goes wrong.

Reproduces explosively and is very hard to fully remove once introduced.

KEEP EXPLORING

Plants with similar growing conditions.

Matched from the PlantLab database using light, CO₂, difficulty, feeding demand and placement.

Shrimp Bites

Duckweed

About Duckweed

What this plant needs.

Placement + size

Energy demand

Where it feeds

Useful parameter range

How to plant it.

What to expect after planting.

Propagation

Acclimation

What usually goes wrong.

Plants with similar growing conditions.

Giant Duckweed

Amazon Frogbit

Dwarf Water Lettuce

Fairy Moss

Floating Fern

Hornwort