Growing Green – Live Mosses for Aquariums

I love a green aquarium…not green in the algae-covered, pea soup kind of way, but green as in dense with varying colors and textures of aquatic plants. We all know that there are many types of aquarium plants, from slow growing Anubias to massive Echinodorus, but one of the often overlooked groups is the mosses. These colonies of simple, prehistoric plants have a special niche in the aquarium when it comes to aquascaping, and they’re also really useful to many types of fish. Here’s a little primer on common mosses for aquariums and what they can bring to your tank.

About Mosses

Mosses aren’t like other plants. They’re simpler in structure, lacking roots and the thick vascular leaves of true plants. These plants don’t blossom or produce seeds.  Most mosses reproduce with spores, relying on moisture to fertilize and create the next generation. Aquatic mosses simply spread, creating new plants with their existing vegetation, so a small portion can populate a vast area. Simply place or anchor small bits or strands where you want them to grow and, under the right conditions, you’ll have lush mounds in just a few short weeks. 

Moss in Aquariums

Moss can play some very special roles in your aquarium. Mosses have the perfect capability of softening harsh areas of rock and wood, creating a seamless, natural aquascape. They can look well manicured and precise, or be allowed to grow wild, changing the dynamic of the aquarium as they spread. Besides their very cool growth habits, freshwater fish and inverts live the stuff! The feathery green strands create perfect hideaways for small fish and invert species. They’re a perfect medium for many species where eggs can be laid. When the babies hatch, they find themselves under the protection of the dense vegetation.

Common Mosses

Here are some of the more common aquatic mosses offered for aquariums and some details to help you choose the type that may suit your situation best.

Java Moss (Vesicularia dubyana) is probably the most commonly offered type of moss for aquariums.  Its long, thin, stringy strands are often left to float in a mass, but the strands will easily attach to solid surfaces if anchored. Java Moss is quite undemanding and can grow in low light, low CO2 environments. They prefer slightly warmer temps and will grow quickly when kept in slightly warmer water. Java Moss may also grow terrestrially (out of water) in warm, damp conditions.

Willow Moss (Fontinalis antipyretica) is also a common find. The strands of Willow Moss are a little more lush, almost resembling a weeping willow tree branch if you look closely. The green tends to be slightly paler in this species than in Java Moss. Willow Moss prefers water that is on the cooler end, and may brown if the water is too warm. It also needs slightly brighter light to thrive. This moss is great for smaller tanks and terrariums/paludariums where it will happily grow in low flow cascades and very moist areas.   

Christmas Moss (Vesicularia montagnei) is the one I wish we would see more often. This lush, bright, fast-growing moss grows in heavy, pyramidal strands (much like a christmas tree) and they have a lovely draping effect once established. Sadly the market is still pretty slim (at least in our neck of the woods) and it isn’t something frequently offered in stores; it is found from time to time on forums and via aquarists with established masses for trade if you can find them.

Liverwort (Pellia sp.) the ribbon-like fronds of these liverworts are great for aquatic or moist terrarium environments. They’re nearly transluscent, and the branching “leaves” grow in ruffled layers for a very interesting focal point. Anchor small pieces to rock or wood, or press small strands into the substrate to start a pellia carpet. These tolerate a broad range of conditions including low or high CO2, low or high lighting (those bits nearer the light tend to be more curly and compact), and temps, though it prefers cooler temps.

Riccia (Riccia fluitans) or leafy liverwort is a gem…it is rather delicate to handle but the slender, lacey, lime-green layers can be gorgeous once you get them established. Keep Riccia trimmed and maintained; it has a tendency to want to float, so as clusters form, the pull to the surface grows and chinks can break off on their own. Riccia is a favorite for bettas and killis; floating mats are ideal for surface dwellers and floating nest breeders. Other fish love to eat it!

Moss Balls (Chladophora aegogrophila) are a bit of an anomaly…these are colonies of filamentous algae that take the form of a sphere. These are not actually a moss, but nonetheless add great interest by their unique shape alone. They do not need to be maintained like the mosses listed, other than to brush debris from their velvety surface from time to time. They like cooler water, low light, and moderate flow keeps them clean and cool.

Mounting and Maintenance

Moss is versatile and easy to play with. It will grow whether simply floating in the water column or anchored or tied to a solid surface. Many aquarists like to tie thin clusters of moss to rock or driftwood with string or fishing line to create interesting live decorations in their tanks. Mosses can also be trained to the floor of the tank, grabbing onto the substrate or anchored with a mesh frame to create a carpet-like effect. Very creative and patient growers even use mosses to create a green wall; a living background of moss. This is achieved using plastic mesh frameworks as well, but the mesh is anchored to the back glass of the tank and the moss grows through creating a vertical surface. These plants are rather opportunistic in fact, and they can grow onto practically any damp surface including glass, filters and other plants.

Preferred lighting, flow and temperature will depend on the moss you choose. Some prefer lower light and will do best in shady areas of the tank, while others need bright light to maintain compact growth. Tropical species may grow faster in warmer water, while others prefer cooler water. You may have great success with some species, but fail with others. Experimentation will pay off!

Once established you may need to prune and shape your moss to keep desired shapes and to prevent the moss from encroaching on other objects in the tank. Don’t be afraid to pluck away nice chunks, these plants are forgiving and tend to recover quickly under good conditions. Thin dense areas of growth to prevent dead spots underneath mounds, and be sure to genlty jostle or even vacuum your moss with a small sipon to remove accumulations of dirt and waste from the fiberous fronds. You’ll have plenty of moss to use in other tanks or to share with other planted tank enthusiasts.  

 

Java Moss image referenced from wikipedia and originally posted by Buchling

Riccia image referenced from wikipedia and originally posted by Piotr Kuczynski

Willow Moss image referenced from wikipedia and originally posted by