Aquatic mosses are some of my favorite aquarium plants because they instantly create the look of a natural ecosystem. When you look at a tank full of mature moss it makes you think of river beds, waterfalls, and shaded grottos.
While moss can be untidy and challenging to grow, Christmas Moss is neither! It’s not as easy to grow as some other aquatic mosses. But with the information in this guide you’ll be ready to grow one of the most beautiful mosses in the hobby!
What is Christmas Moss?
Christmas Moss is an East Asian moss that belongs to either the genus Vesicularia or Taxiphyllum. As you might imagine, the exciting world of moss taxonomy is not at the bleeding edge of scientific research. You will find references to it in either genus so just be aware that it’s very closely related to all of the mosses that share these scientific names.
Its close cousins include the much more popular Java Moss (Vesicularia dubyana), Flame Moss (Taxiphyllum ‘flame’), Taiwan Moss (Taxiphyllum alternans ‘Taiwan’) and several other mosses you’ve never heard of.
Moss tends to be slow growing and kind of fussy but absolutely beautiful under the right conditions. Fortunately, moss is not expensive to buy, doesn’t need fancy soil or strong lighting, and you can spread it very easily. Christmas Moss is also not only one of the most beautiful but an easier kind to grow as well!
- Common Name: Christmas Moss
- Scientific name: Vesicularia montagnei
- Origin: East Asia
- Height: 1-2 inches
- Light Requirements: Low to Medium
- Growth Rate: Slow to Moderate
- Ease of Care: Moderate
Christmas Moss Care
This section covers Christmas moss care topics such as lighting requirements, water parameters, and more.
Light Requirements
Christmas Moss doesn’t need intense lighting but it does need good quality light output. You may not know this but not all lights are created equally. There’s lighting and then there’s photosynthetically active radiation (PAR).
Even a bright incandescent or standard fluorescent fixture may leave you with weak, stunted plants. This is because only a specific slice of visible light is what plants use to produce sugars via photosynthesis.
Aquarium full spectrum LED lighting ensures that your Christmas Moss stands a fighting chance. Fortunately, you don’t need especially intense light to grow mosses. The majority are low to medium light plants.
High lighting doesn’t cause them to grow much faster but it can cause them to get coated with algae. Better to stick with lower light levels for Christmas Moss.
Planting & Propagation
Like most mosses, Christmas Moss is an epiphyte, meaning it doesn’t root into the substrate. Instead, you can attach it directly to rocks, driftwood, and other hard surfaces. This makes Christmas Moss fantastically versatile because so long as it has light it will spread like a creeping carpet with no effort from you.
This means you can use any substrate you want, gravel or sand. Neither makes a difference to Christmas Moss. Still, I would use a planting substrate in any tank with live plants. While the Christmas Moss won’t be sending roots down it will benefit from a proper plant substrate.
Substrates like Eco Complete and Fluval Stratum have a high cation exchange capacity (CEC), allowing them to bind to plant nutrients and slow release them back into the water column for Christmas Moss to benefit. Otherwise, fertilizers dosed into the water column tend to get quickly absorbed by stem plants and algae before your moss gets a chance at uptaking them.
Moss Dry Start Method
If you’re looking to get dense growth out of Christmas Moss and other species I recommend trying the Moss Dry Start Method! It takes a little (a lot) longer to get up and running compared to simply gluing or attaching your moss to a hard surface. But the results really speak for themselves!
The advantage of using the Dry Start Method on moss is that it will both establish itself and spread much more quickly than it typically would when grown underwater. This is because the air contains several times more CO2 than even CO2-injected water does.
Using a CO2 injection system we typically aim for 20-30 ppm as higher becomes toxic to fish and shrimp. Meanwhile the atmosphere contains roughly 400ppm of CO2. Many other plants that also grow emersed can be dry started for better results, including Dwarf Sagittaria, most Sword Plants, and Dwarf Hairgrass.
In order to dry start a plant we need to keep the growing environment moist but not submerged. Our Christmas Moss can be pulled into pieces and applied directly to rocks or driftwood. But I prefer taking a more daring approach: running it through a blender and painting the slurry directly onto hard surfaces!
Moss is a non-vascular plant, meaning it has a more primitive, far simpler structure than more familiar looking plants like trees and stem plants. You can shred moss on a cellular level and it will still regenerate!
By painting our moss slurry onto stones and rocks, it will naturally grow in as a thick, even carpet. Using clumps of moss results in a more patchy growth pattern.
A moss slurry also means that a small handful of moss, which can be expensive, stretches much further. A solid clump of moss may also decide it wants to grow somewhere else. Blended moss is actually easier to aquascape with!
Once you’ve painted or attached Christmas Moss to a damp hard surface, you can cover your tank with saran wrap, which locks in the moisture but also lets in light. Keep the humidity close to 100% by misting several times a day with distilled water dosed with a small amount of liquid fertilizer and let the lights blaze for 12-18 hours a day.
Some Dry Start aquarists advocate using yoghurt in the blended moss mix to provide nutrients. This absolutely can work but it can also grow fungus so I prefer to use aquatic plant fertilizer at 1/10th the usual dose.
Unlike algae, your moss can grow emersed. Within 3-4 weeks you should start seeing tiny patches of moss forming if you blended it or some tendril spreading if you used clumps. And by 8 weeks you should have a much thicker carpet of moss. Now is the time to flood the tank!
Fertilizer, CO2 & Water Chemistry
The good news is that once Christmas Moss is established it’s very easy to look after. It does like a little more light but it doesn’t really need much in the way of fertilizer. If you’re keeping fish and shrimp in the same aquarium it will get nearly all of the nutrients it needs from the animals.
Dwarf Shrimp like Red Cherry and Amano Shrimp are especially good tank mates for Christmas Moss. They pick through the fine “leaves,” pulling off bits of algae and biofilm to eat. This prevents the slow growing moss from being colonized and overwhelmed by invading microorganisms.
If you’re growing live plants then any fertilizers you add will also be appreciated by the moss. Christmas Moss may not be fertilizer-hungry but it does like carbon dioxide. Many mosses grow in the splash or transition zone between the water and air. Therefore they tend to get much more CO2 than fully aquatic mosses.
I recommend using DIY CO2 or a CO2 injection system if you want to be 100% certain your Christmas Moss thrives. However it’s not absolutely mandatory and your moss will still establish itself (slowly) without it. It will also carpet much more slowly without CO2 but it won’t die.
Christmas Moss also prefers very moderate water conditions. Like most aquatic mosses (except Java Moss) it prefers moderately cool conditions. Room temperature to moderately tropical temperatures (65-75℉) are best for this species.
Any warmer tends to cause its growth to stall out. It may even brown and die if kept too warm. Colder water holds more carbon dioxide as well, which this moss craves.
Christmas Moss isn’t too picky when it comes to water chemistry either but it does prefer being kept as close to neutral pH as possible (pH 7.0). A slight swing towards acidity or alkalinity (pH 6.5-7.5) is no cause for concern but neutral best suits it.
Aquascaping With & Propagating Christmas Moss
Christmas Moss grows quite a bit slower than its close cousin Java Moss. The flip side of Christmas moss is that it’s much more beautiful thanks to its very distinctive growth habit.
Christmas Moss is aptly named. Once it gets established and begins to spread, it forms a triangular shape that looks a lot like a fir tree. Specifically, the Douglas Fir (Pseudotsuga menziesii,) a North American conifer that has been popular for use as Christmas trees since the 1920’s.
Its tidy and well kept appearance makes it a welcome addition to aquariums that have a lot of flat surfaces that receive ample lighting that need covering. Christmas Moss won’t typically grow too far into the shade. So the broad tops of driftwood and rocks are the best places to attach it.
Christmas Moss also doesn’t grow too tall. A few other relatives such as Flame moss do grow upwards so this is a better moss choice if you’re looking to fill the vertical dimension. Christmas Moss does grow laterally, however. And the triangular, branching shape is perfectly suited to its creeping style of growth.
It will take months to fully fill in but it’s still faster than most other mosses except Java Moss. I’ve personally found that Fissidens mosses, Hookeraceae, and other mosses are absolute snails compared to Christmas Moss. They take forever to fill in even with carbon dioxide addition…
It’s also worth mentioning that there is a ‘Mini’ Christmas Moss that’s very rare but well worth trying! It has a compact growth pattern but still has the same Christmas tree shape of the standard moss. The delicate fronds of this variety would be absolutely perfect for a 3-5 gallon nano tank.
Christmas Moss vs Java Moss
Since Christmas and Java Moss are both of the genus Vesicularia (formerly Taxiphyllum) they get compared to one another very often. They are superficially very similar and a handful of one or the other look pretty much the same.
It’s no until you let them grow for a few weeks that the differences become obvious. So what’s the difference between Christmas Moss and Java Moss and which is right for you?
Well if you have a brown thumb for growing plants Java Moss is absolutely bullet-proof. You can seriously grow this plant anywhere. It doesn’t need specialized lighting and it will grow under standard incandescent bulbs. It also somehow spreads like wildfire with no added carbon dioxide or fertilizer. Fish waste is more than enough food for it.
You’ll be ripping handfuls out of your tank in a few months. Java Moss also grows in all temperatures and water conditions, even temperatures beyond 80℉, which stresses most mosses. Unsurprisingly, being from Indonesia, which sits right on the equator, it makes perfect sense that this moss loves heat.
Christmas Moss, as I’ve explained above, is a bit more needy. It’s not as hard to keep as most carpeting or red plants, which are usually high light, carbon dioxide, and nutrient lovers. But it’s a step up on the challenge scale from low light plants.
The benefits of Java Moss are unfortunately also its weaknesses. Because it grows like crazy it doesn’t form a tidy little clump like Christmas Moss. Java Moss forms thick ropy tangles that just creep in all directions.
If you want more of a chaotic jungle appearance then it works beautifully. But you’ll have to keep trimming it back continually or it will fill in nearly all of the available space.
Christmas Moss grows laterally rather than vertically and slowly but not too slow. And the tree-like fronds are beautiful and need no maintenance as it would take years for it to get too bushy. It’s both low maintenance and attractive all on its own.
Conclusion
The moss world is a surprisingly interesting subsection of the aquarium plant world that most aquarists are unfamiliar with. If you want something a little more challenging but much more rewarding than Java Moss, I recommend you give Christmas Moss a try!
All it takes is a little more attention to lighting and water conditions as well as a lot more patience. But you’ll be richly rewarded with an aquascape like no other!
