Phoenix moss

The individual stems grow outward and upward in a way that looks like small green flames, which is where the common name comes from. Fissidens fontanus is a temperate moss found across North America and Europe, and it has a different growth habit from the tropical mosses most aquascapers are used to. Instead of sprawling horizontally like Java Moss, it forms upright tufts that stay compact under the right conditions.

It attaches readily to wood and stone but takes time to establish. The initial growth is slow, and patches can sit looking unchanged for several weeks before they start spreading. Once settled, it produces new shoots from the base and the clump thickens gradually. Trimming encourages denser growth but is not needed often.

Light requirements are flexible — it grows in low light but stays more compact under moderate levels. CO₂ injection speeds growth but is not essential. The real constraint is temperature: it prefers 18 to 25 °C and does not do well in warm tropical tanks above 26 °C for extended periods. Soft, slightly acidic water at pH 5 to 7.5 suits it best.

In temperate and coldwater setups it is one of the few mosses that stays healthy year-round. It is also winter hardy, so it can be used in outdoor ponds in mild climates. Propagation is by splitting a clump or cutting off daughter plants once they have visible rhizoid growth.