Canadian waterweed

Elodea canadensis

Also known as Canadian pondweed, American waterweed, Anacharis, Common waterweed

FreshwaterStemCuttingsfragmentation

Canadian waterweed (Elodea canadensis) — Christian Fischer · CC BY-SA 3.0

Care at a glance

Light: Low light
CO2: No CO₂ needed
Growth rate: Fast
Placement: Background
Type: Stem
Temperature: 39–75°F (4–24°C)
pH: 6.5–8.0
Hardness: 5–20 dGH
Max height: 23.6 in (60 cm)
Spread: 2 in (5 cm)
Nutrient uptake: Water column
Growth region: Submersed
Difficulty: Beginner
Origin: Native to lakes, ponds, and slow rivers across temperate North America.
Family: Hydrocharitaceae

Overview

Canadian waterweed is a hardy beginner plant that thrives in cool water and low to medium light without CO2. It can be planted loosely in the substrate or left floating, and it grows fast enough to soak up excess nutrients and help fight algae. Trim as needed, since it prefers cooler tanks and can struggle in warm tropical setups.

In the wild

Elodea canadensis has slender, brittle stems densely set with small, dark green leaves in whorls of three. It grows in cool lakes and slow rivers, often forming thick underwater stands. It roots loosely or simply drifts, absorbing nutrients straight from the water.

Good to know

Elodea canadensis belongs to the frogbit family, Hydrocharitaceae, and is distinct from the similar-looking Egeria densa, which is a separate genus. Plants are either male or female, and outside North America almost all spread is by fragmentation rather than seed. It was one of the first aquatic plants used to demonstrate photosynthesis in classrooms.

Did you know

A classic photosynthesis demonstration plant in classrooms, it is also a serious invasive species in Europe, Asia, and Australia, so it should never be released into the wild.