Ceratophyllum demersum Hornwort

Ceratophyllum demersum, the Common Hornwort, is one of the most widely distributed aquatic plants on Earth and a perennial favourite in the aquarium hobby. It grows without substrate as a free-floating or loosely anchored stem plant, producing dense whorls of dark-green, forked needle-like leaves along brittle, segmented stems. Its explosive growth rate makes it a powerful nutrient exporter, helping control algae in newly established and heavily stocked tanks. It provides excellent cover and spawning sites for fish and invertebrates and is tolerant of an extraordinary range of water conditions including cold, hard and alkaline water. An invaluable utility plant for any aquarist.

Light: Low to medium (15–35 PAR); grows vigorously even under modest lighting. CO2: Not required; one of the few stem plants that grows excellently without CO2. Fertilisation: Absorbs nutrients directly from the water column; rarely needs supplementation. Placement: Background floating or loosely anchored; can shade lower plants without management. Propagation: Simply break stem sections; each fragment develops independently.