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 Giant Duckweed

A larger duckweed with reddish undersides and multiple roots.

Giant Duckweed is a bigger relative of common duckweed, with rounder fronds, purple-red undersides, and several dangling roots. It's an efficient nutrient exporter and easy fry cover, though it spreads fast like all duckweeds.
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.

Spreads quickly and is hard to remove completely.