Duckweed

Lemna minor

Plantae›Tracheophyta›Magnoliopsida›Araceae

📍 Worldwide

Duckweed is the smallest flowering plant and one of the fastest-growing aquatic plants available. It provides effective nutrient export and surface shade while serving as live food for herbivorous fish. It can quickly cover the entire surface if not managed.

Tank Mates

Otocinclus

Herbivorous algae eater that won't damage duckweed; benefits from shade provided by plant coverage

excellent

Red Cherry Shrimp

Shrimp graze on algae and detritus without harming duckweed; thrive in shaded environments

excellent

Dwarf Gourami

Appreciates surface vegetation for shelter; won't uproot or consume duckweed

good

Neon Tetra

Small peaceful fish that benefit from duckweed shade and won't disturb the plant

excellent

Amano Shrimp

Excellent algae control companion; won't damage duckweed and prefers planted environments

excellent

Java Moss

Companion plant with similar low-light tolerance; creates dense cover when grown together

excellent

Common Diseases

Nutrient Deficiency

Symptoms

Yellowing fronds, stunted growth, pale coloration, reduced reproduction rate

Treatment

Dose all-in-one liquid fertilizer weekly; test water for nitrogen, phosphorus, and iron levels; increase water change frequency to boost fish bioload

Algae Overgrowth on Fronds

Symptoms

Green or brown algae coating duckweed surfaces, reduced light penetration, plant decline

Treatment

Increase water circulation with aeration; reduce light duration to 8-10 hours daily; manually remove heavily algae-covered fronds; introduce algae-eating fish like Otocinclus or Siamese Algae Eater

Root Rot (Minimal Risk)

Symptoms

Fronds detaching prematurely, mushy appearance, foul odor from decaying plant matter

Treatment

Improve water circulation and oxygenation; remove dead fronds immediately; ensure water parameters remain stable (pH 5.0-8.0); perform 25% water changes weekly