ludwiga repens in tank

Hornwort Overview

Scientific Name: Ceratophyllum demersum
Common Name(s): Hornwort, Coontail
Origin: Cosmopolitan (found worldwide in freshwater habitats)
Plant Type: Stem plant (floating or rooted)
Typical Height: 20–100+ cm (can grow long and free-floating)
Difficulty Level: Very Easy
Lighting: Low to Medium
Temperature: 10–28°C

Hornwort is one of the hardiest and most adaptable plants in the freshwater aquarium hobby. Naturally found in lakes, ponds, and slow-moving rivers, it grows either floating freely or loosely anchored in substrate. Its fast growth, ability to absorb excess nutrients, and low maintenance requirements make it especially popular for beginners, breeding tanks, and aquariums prone to algae.

Aquarium Requirements

Lighting Requirements:
Thrives in low to medium lighting. Higher light encourages faster growth but is not essential.

Temperature Range:
10–28°C, making it suitable for both tropical and coldwater aquariums.

pH Range:
6.0–7.5 (highly adaptable to different water conditions)

Placement in Tank:

  • Can be used as a background plant when weighted or planted loosely
  • Often used as a floating plant for natural coverage

Growth Rate:
Fast-growing, especially in nutrient-rich water.

Substrate, Fertilisation & CO₂:

  • Does not require substrate (lacks true roots)
  • Absorbs nutrients directly from the water column
  • Benefits from liquid fertilisers but often thrives without them
  • CO₂ is not required

Growth and Appearance

Hornwort has a unique, bushy appearance made up of whorled, needle-like leaves along long stems.

  • Leaf Structure: Fine, forked leaves arranged in circular whorls
  • Colour: Bright to dark green depending on conditions
  • Texture: Soft, feathery, and slightly spiky

Submerged Growth:
Forms dense, flowing clusters that can grow rapidly and fill large areas of the tank.

Emersed Growth:
Rare in aquarium settings, as Hornwort prefers to remain fully submerged.

In aquascaping, it creates a wild, natural look and adds movement as it gently sways in the current.

Care and Maintenance

Hornwort is extremely low-maintenance but benefits from occasional care:

  • Trim regularly to control rapid growth and maintain shape
  • Remove shed needles, as it can drop leaves during environmental changes
  • Keep water parameters stable to minimise shedding
  • Thin out dense areas to allow light penetration
  • Perform regular water changes to maintain water quality

Its rapid growth makes it excellent for improving water conditions, especially in new setups.

Aquascaping with Hornwort

Hornwort is highly versatile in freshwater aquariums:

  • Ideal as a background plant for filling space quickly
  • Commonly used as a floating plant for shade and cover
  • Excellent for breeding tanks, providing shelter for fry
  • Helps reduce algae by absorbing excess nutrients
  • Creates a natural, slightly untamed look in aquascaping layouts

It pairs well with floating plants, mosses, and slower-growing species, helping balance nutrient levels in planted aquariums.

Hornwort at Smith's Aquatics

At Smith’s Aquatics in Stockton-on-Tees, we regularly stock a variety of live aquarium plants, including Hornwort.
Our team can help you with:
□ Choosing suitable plants for your aquarium
□ Advice on lighting and plant nutrition
□ Selecting plants compatible with your fish and setup
□ Creating balanced planted aquariums

Visit our store to explore our current selection of live aquarium plants and find the right species for your aquarium.