PlantFreshwaterBeginner

Hornwort

Ceratophyllum demersum

Also known as: Common Hornwort, Coon's Tail, Coon’s Tail, Hornwort, Coontail

A fast-growing, nearly indestructible plant that thrives on neglect.

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About

Hornwort (Ceratophyllum demersum) is one of those plants that practically grows itself, making it a go-to recommendation for anyone just getting into planted tanks. The plant has a distinctive, almost prehistoric look. Dense whorls of stiff, needle-like leaves arranged around a central stem, giving it that bushy, feathery texture the common name Coontail describes well. Native across the British Isles and into Scandinavia, it grows naturally in still or slow-moving freshwater, where it often floats freely rather than anchoring into substrate. In the aquarium it behaves the same way. You can plant it loosely in the substrate or simply let it drift near the surface, and it will grow either way. That adaptability extends to water conditions too, tolerating a wide range of hardness and pH values without complaint, which is part of what makes it such a forgiving choice for newer keepers. Growth can be genuinely rapid under decent lighting, so regular trimming keeps it from crowding out tankmates. The dense foliage also provides excellent cover for fry and shy species. One minor quirk to know: the plant sheds its tiny leaves readily when disturbed, and those needles can clog filters if you're not careful during maintenance.

At a glance

Type: Plant
Water: Freshwater
Origin: England (England, Wales, Scotland, Isle of Man); Ireland (Ireland, Northern Ireland); Denmark

Water parameters

Temperature: 60–86°F
pH: 5.5–8.5
Hardness: 2–25 dGH

Care guide

Hornwort thrives with minimal fuss but grows quickly and needs regular trimming to prevent overgrowth. Plant loosely in substrate or allow it to float freely. Both methods work equally well. Provide moderate to bright lighting to encourage dense growth; in low light it becomes leggy. The plant tolerates a broad range of water conditions and requires no special fertilization in established tanks. Handle gently during maintenance as the needle-like leaves shed easily and can accumulate in filter intakes. Prune regularly by removing top sections to encourage bushier growth and prevent shading of lower plants. The dense foliage makes it invaluable cover for fry and nervous fish. In cooler tanks it grows more slowly, which may actually be preferable if space is limited.

Breeding

Hornwort propagates via stem cuttings with ease. Simply trim healthy stem sections and plant them loosely in the substrate or allow them to float; they'll develop roots within days to weeks. Any section with a few whorls of leaves will establish successfully. For faster propagation, take cuttings from actively growing tips and maintain strong lighting and stable water conditions. No special nutrients or conditions are required beyond those needed for general growth. This plant reliably produces new plantlets and can fill a tank rapidly under ideal conditions.