Hornwort (Ceratophyllum demersum) Care Guide
A fast-growing floating stem plant with fine needle-like leaves that absorbs excess nutrients rapidly. Excellent natural water purifier that helps control algae in new and established tanks.
Compiled by Aquairi from published sources · Published
Overview
Ceratophyllum demersum is an aquatic plant in the family Ceratophyllaceae. A fast-growing floating stem plant with fine needle-like leaves that absorbs excess nutrients rapidly. Excellent natural water purifier that helps control algae in new and established tanks.
Taxonomy
- Family: Ceratophyllaceae
- Genus: Ceratophyllum
- Scientific name: Ceratophyllum demersum
- Other names: Coontail
Habitat
Has a cosmopolitan distribution, native to every continent except Antarctica. Free-floating, rootless plant; stems carry whorls of 6-12 stiff, brittle forked leaves and form turions that overwinter on the bottom. Allelopathic toward phytoplankton and cyanobacteria.
Growth requirements
- Light: low (≈30-50 PAR at substrate)
- CO2: optional (CO2 improves growth and coloration)
- Temperature: 15-30 °C
- pH: 6-8
- GH: 3-18 °dGH
- Substrate: any (rootless or floating)
- Nutrient demand: low
- Growth rate: fast
- Difficulty: beginner
Placement
- Recommended placement: floating at the surface
- Maximum height: 60 cm
- Trim every: 7 days
Propagation
In cultivation the plant is propagated by stem cuttings (replant the upper portion after trimming).