TankBud

Phoenix moss

Fissidens fontanus

Also known as Fissidens, US Fissidens, Octodiceras fontanum

FreshwaterMossRhizome division

Phoenix moss (Fissidens fontanus)
Aquarium Plants Factory · Used with permission

Care at a glance

Light
Medium light
CO2
CO₂ beneficial
Temperature
68–82°F
20–28°C
Max height
1.2 in
3 cm
Growth rate
Slow
Placement
Epiphyte
Type
Moss
pH
6.0–7.5
Hardness
2–15 dGH
Spread
3.9 in (10 cm)
Nutrient uptake
Water column
Growth region
Submersed
Difficulty
Medium
Family
Fissidentaceae
Origin
North America (widespread in the United States), submersed on wood and rock in rivers, streams, and ponds

Overview

A slow but rewarding carpet and accent moss with a fine, feathery look. Tie or glue thin pieces onto wood or stone, since thick wads trap debris and brown out underneath; it grips well once established. It is more light- and CO2-responsive than easier mosses, so medium light with added CO2 gives compact, well-defined fronds, while low-tech tanks grow it loosely and even more slowly. Expect a few months before a tied piece spreads into real coverage.

In the wild

A genuinely aquatic moss native to North America and widespread across the United States, where it grows submersed on submerged wood, rock, and other surfaces in rivers, streams, and ponds. Unlike many aquarium mosses, it lives its whole life underwater rather than as a bog plant. It forms low, dense mats of overlapping feathery fronds.

Good to know

Fissidens fontanus is a true moss in the family Fissidentaceae and was historically also placed in the genus Octodiceras. Its leaves have an unusual structure with a sheathing base that wraps the stem, giving the distinctive flat, two-ranked, fern-like frond. It is one of relatively few mosses adapted to permanent submersion.

Did you know

Did you know phoenix moss is one of the few aquarium mosses native to the United States rather than tropical Asia? It was a fairly late arrival to the hobby and is still sometimes sold as 'US Fissidens' to distinguish it from imported Asian Fissidens types.

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