Hornwort

Key Characteristics of Hornwort (Ceratophyllum demersum)

• Scientific Name: Ceratophyllum demersum
• Common Name: Hornwort, Coontail, Rigid Hornwort
• Hardiness: Very Easy (Often cited as the most beginner-friendly and adaptable plant).
• Appearance: Features numerous side shoots and dense whorls of bright green, stiff, and brittle needle-like leaves. The overall mass is bushy and resembles a raccoon’s tail (hence, Coontail).
• Root Structure: Lacks true roots. It absorbs all its nutrients directly from the water column through its stems and leaves. It can anchor itself using modified, leafless stems, but these are not true roots.
• Size & Growth: Has a fast growth rate (often several inches per week) and can reach lengths of 3 feet or more, quickly filling the tank.
• Lighting: Highly adaptable, tolerating low to high light, but performs best under moderate light.
• Planting:
  • Floating: Most commonly left free-floating on the surface, where it excels at nutrient removal and provides excellent shade.
  • Anchoring: Can be lightly anchored in the substrate or weighted down, but the buried stem sections may eventually rot or shed leaves (shedding is a common trait, especially when moved).
• Benefits: Highly effective at absorbing excess nitrates and phosphates from the water, which helps control algae. It provides excellent, dense cover for fry and timid fish.
• Allelopathy: It is known to release chemicals that inhibit the growth of certain types of algae (like blue-green algae and phytoplankton).