Phoenix moss
Fissidens fontanus
Also known asPhoenix moss · Limp pocket moss · Fountain moss
Water parameters
Light and nutrients
Substrate type: epiphyte. Propagation: fragmentation.
Substrate compatibility
| Substrate | pH effect | Nutrient load |
|---|---|---|
| Wood and rock mounts (Hardscape mount) | varies | none |
| Aquasoil (ADA Amazonia) | lowers pH | very high |
| Mineralized clay substrate (Seachem Fluorite) | neutral / inert | moderate |
| Inert sand (Pool filter sand) | neutral / inert | none |
With fish
Origin and habitat
An aquatic moss of the family Fissidentaceae, Fissidens fontanus, called phoenix moss or limp pocket moss. It is native to North America, most common in the eastern and midwestern United States and sparse in Canada, and has been introduced widely beyond that, turning up across Europe, the Mediterranean, Mexico, Chile, Australia, Africa and the Arabian Peninsula. The fronds are flat and feather-like, the small lance-shaped leaves 2–7 mm long, each with a clear midrib and a folded pocket-like lobe at the base, growing in neat layered rows; that orderly, fern-like structure is what sets it apart from the bushy tangle of Java and Christmas moss. In the wild it clings to rocks and wood in cool, clear streams and springs, and in the hobby it is prized for fine nano aquascaping.
Care notes
Attach it to rock, driftwood or mesh with a dab of glue or thread, and over a few weeks its rhizoids take hold; it can be set horizontally or vertically. It tolerates low light but, unlike most aquarium mosses, it genuinely does better with more, and it is more light- and CO2-hungry than Java or Christmas moss, so moderate-to-strong light plus CO2 give the densest, fullest fronds, while too little light leaves it thin. Growth is slow even then. Keep it in clean, well-circulated water around 20–28°C, since detritus settling on the flat fronds blocks light and feeds algae; wave a hand near it at water changes to clear settled muck. Trim with scissors to shape it as it spreads outward in layers from the attachment point. It is a top choice for shrimp tanks, the flat fronds giving excellent biofilm grazing and cover for shrimplets and fry. It costs more than Java moss because it propagates slowly at the nursery. It is an ornamental aquatic moss, not a crop, so it is unsuited to media-bed aquaponics or hydroponics.