How much light does Christmas Moss need?

Medium light, around 30–50 µmol·m⁻²·s⁻¹ of PAR. Watts are not comparable between fixtures; PAR is. If the manufacturer does not publish PAR, pick one band lower than the tank depth suggests.

Does Christmas Moss need CO₂?

It is optional. Marked "optional": with CO₂ it grows faster and tighter, without it still does fine.

What water does Christmas Moss want?

20–26 °C, pH 5.5–7.5, 1–10 dGH. At 9 dGH wide it is one of the more forgiving ranges.

How fast does Christmas Moss grow, and where does it go?

Growth rate: slow. Placement: foreground / attached. Substrate: no substrate needed. Difficulty: moderate.

G-02 / 03Freshwater

Christmas Moss圣诞莫斯

Vesicularia montagnei · Hypnaceae

Its side shoots form layered feathers; it dislikes heat and hard water and fills in far slower than Java moss.

Illustration to come

G-02 / 03 · Christmas Moss Vesicularia montagnei

SpecificationsPlant atlas

Name: 圣诞莫斯
Scientific name: Vesicularia montagnei
Family: Hypnaceae
Origin: Stream rocks and tree roots of South America (the Brazilian Amazon basin)
Light: Medium light
PAR: 30–50
CO₂: Optional
Hardness: 1–10 dGH
Growth: Slow
Placement: Foreground / Attached
Substrate: No substrate needed
Level: Moderate

Water requirementsFreshwater

Temp.20–26 °C

pH5.5–7.5

Hardness1–10 dGH

Alkalinity1–6 dKH

Units: temperature in °C, hardness in German degrees (dGH / dKH), marine salinity as specific gravity at 25 °C, volume in litres. These are the values recorded for the species and do not follow the site unit switcher.

Growing notes

1The neat Christmas-tree layering only appears between 20 and 25 °C; above 28 °C it thins and yellows visibly.
2Typical growth needs water below 4 dGH and steady CO2; in harder, more alkaline water the fronds stay thin.
3Only shorten over-long main stems when trimming; a full crew cut costs months before the layering returns.
4Medium light is enough; under strong light hair algae wraps it and the only fix is to cut the moss away with the algae.
5It grows slowly, so allow two to three months to fill in when it is the main feature.

Frequently asked questions

How much light does Christmas Moss need?: Medium light, around 30–50 µmol·m⁻²·s⁻¹ of PAR. Watts are not comparable between fixtures; PAR is. If the manufacturer does not publish PAR, pick one band lower than the tank depth suggests.
Does Christmas Moss need CO₂?: It is optional. Marked "optional": with CO₂ it grows faster and tighter, without it still does fine.
What water does Christmas Moss want?: 20–26 °C, pH 5.5–7.5, 1–10 dGH. At 9 dGH wide it is one of the more forgiving ranges.
How fast does Christmas Moss grow, and where does it go?: Growth rate: slow. Placement: foreground / attached. Substrate: no substrate needed. Difficulty: moderate.