Willow Moss

Willow Moss (Fontinalis antipyretica) is a true cold-water aquatic moss native to fast-flowing streams and rivers across Europe and North America. Its long, three-ranked, densely leafed stems resemble the drooping branches of a willow tree when anchored to submerged wood in moving water — which is the source of its common name. The stems are dark green, robust, and structurally quite different from the finer-textured branching mosses typical in tropical aquascaping.

F. antipyretica is best suited to cool aquariums kept at 15–22°C and loses vigour above 25°C. It thrives in well-oxygenated, clean water and performs well in temperate or cold-water setups housing native fish, cold-water invertebrates, or species from mountainous biotopes. It does not require CO2 or intense lighting and is quite tolerant of moderate water hardness.

In the aquarium, Willow Moss is attached to driftwood or smooth rock with thread or loose clips, and in moderate flow it will develop its characteristic cascading, willow-branch appearance. It also serves as a beneficial biological filter medium and provides excellent fry shelter in cold-water breeding setups.

Light: Low; the species is adapted to cold, often turbid streams and manages in very low light. CO2: Not required; grows naturally in CO2-rich fast-water habitats without supplemental injection. Fertilisation: Minimal; periodic liquid micronutrient dosing in soft-water tanks prevents deficiencies. Placement: Attach to driftwood or rock in moderate current; cool tanks (15–22°C) are essential for long-term health. Propagation: Cut stem sections of 5–10 cm and tie to new surfaces; regrowth is moderate in cool conditions.