(Unedited version)
Originally appeared in the March 2006 issue of
Tropical Fish Hobbyist Magazine

Mosses are one of my favorite plants for the aquarium. They are so easy to grow and so beautiful. Mosses are in all sorts of different planted tanks, from the lovely Asian to Dutch to the simple family aquarium. Mosses bring beauty and practicality to the aquarium. It's easy to encourage moss to grow on wood or rocks for a naturalizing look, or on the back of a tank. It can be molded almost like topiary. Mosses are also used for breeding fish and it provides cover and a place to eat, hide, and grow for small fish and shrimp.

Mosses are also some of the more interesting plants. They are considered to be the first real plants to develop, and so are among those plants called primitive.

The first photosynthetic organisms developed in the ancient seas some 4 billion years ago. Land plants didn't start developing until about 500 million years ago. Plants, including mosses are believed to have evolved from green algae (Phylum Chlorophyta). They share many of the same characteristics among them; Green algae and plants use the same types of chlorophyll. The cell walls of most green algae and plants are made of cellulose. They both store their carbohydrate reserves as starch.

The actual physical record is sparse due to the soft nature of algae and plants though it's likely one of the filamentous green algae (think hair algae) were the first to try life on land.

The earliest plants to evolve that are still around today were originally grouped together and called the bryophytes. They include the mosses, liverworts and hornworts (not to be confused with the aquarium plant, Ceratophyllum demersum). The bryophytes are all non-vascular. This means they don't have the veins that more advanced plants do to transport water and nutrients throughout the plant. Though the three different bryophytes have similarities and are still grouped together casually, it's more recently been determined that they are not closely related and that the mosses are the most like the vascular plants of the three.

To live on the land plants had to develop a way to retain water in their cells and reproduce in this new environment. Mosses aren't like most plants we're all familiar with. Their little leafy like structures are only one cell thick usually with a mid-rib, but they aren't true leaves. The root like growths are called rhizoids. They rhizoid and leaves of a moss lack the structure of true leaves and roots.

Mosses don't make seeds but create spores. Mosses didn't evolve with insect helpers. They don't have pollen to fertilize the next generation. The fertilization of mosses must occur through water. Usually dew or raindrops is enough for most mosses living on land.

Aquatic mosses can also develop spores but they most often will reproduce vegetatively, especially in the aquarium. A small piece of moss can grow into a new lush bed.

There are approximately 10,000 species of mosses living. They are generally considered to be in three classes; Andreaeopsida, the granite mosses, Bryopsida, the true mosses, and Sphagnopsida, the peat mosses. There is some dissent whether Takakia, another moss like plant, should be included in Andreaeopsida or be in a separate phylum of its own. The mosses we're familiar with in the aquarium are in the class Bryopsida.

Mosses in the aquarium

In the aquarium aquatic mosses are generally very easy to grow. The will tolerate low and high light levels, and will grow on anything, even in bare tanks. Mosses can easily be trained to grow over driftwood or rocks in the aquarium. Mosses will grow in between other plants, giving your tank a lusher look. You can also make a moss wall to cover the back of your aquarium. Usually a plastic mesh or netting is used. Moss is sandwiched between 2 layers and attached to the back and sometimes side walls of the aquarium.

There are three mosses that are most used in the aquarium in the United States. They are; Java moss, Christmas tree moss, and Fontinalis.

Until recently Java moss (Vesicularia dubyana) was generally the most common aquarium moss found for sale in the United States. It's fast growing and tolerates most conditions. I've even had it grow, though more slowly, under incandescent lighting. The leafy structures are smaller in Java moss and it doesn't look as lush as the other aquarium mosses. It's also often a darker green.

Fontinalis has been used in aquariums from early on. It's often found in native waters. There are a number of different mosses that are commonly called Fontinalis. There are more than 50 aquatic mosses recognized in the United States alone, from several families. Though some of these mosses will adapt to aquarium life, they are often more difficult than Java moss or Christmas tree moss. Many of them seem to prefer colder water than that found in the home aquarium. The species of Fontinalis I've grown have had a very fragile and dainty appearance, with larger leaves than the Java moss but not as wide and large as the Christmas tree moss.

Christmas tree moss is a relative new comer, at least on the American aquarium scene. This moss is so called because of its growth pattern which looks like a Christmas tree. It grows extremely well and quickly into large bright green mounds. In many ways it's the most attractive of the common aquatic mosses, with the largest leaves and fullest growth.

Pruning your mosses is easy. You can just pull off what you don't want. Usually it's best to use two hands, one to keep the sections of moss down that you want to keep in your aquarium and one to take that part you don't want out. If you're just thinning a few small bits out though you can easily pick them out with just one hand. The sections you take out can be passed along to another aquarium either one of yours or a friend's. Mosses are also usually popular at fish auctions and some shops will make trades or buy your excess plants. You can also use scissors to trim your moss if you'd like.

You will need to prune your mosses; they will eventually keep growing until they are the only plant in the tank if you let them. Moss will eventually smother out the other plants if you don't keep them trimmed down.

As mosses get more mounded I often just push them down a bit too. Sometimes they get air in them and like to float and sometimes they just keep growing until they get too large. The bad side of just pushing them down is that the moss on the bottom won't get any light and will die off, leaving you a bunch of dead plants under your moss mounds. It's ok to push the mounds down occasionally. Just be aware of the potential and don't do it too much. Be sure to lift the moss mounds occasionally when you're cleaning your tank and vacuum out underneath them.

Mosses are one of the easiest aquarium plants to grow and are extremely attractive and useful. They also have an interesting biological history and exude a kind of mystery of their own. I hope you'll consider trying them in your planted aquarium.

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Welcome to the Jungle | Into The Forest | The Creepy Crawlies | A Clearing in the Thicket | Algae Eaters for the Planted Aquarium
North American Natives | Why things go wrong Pt 1 | Why things go wrong Pt 2 (Algae) | Algae Eating Shrimp | Lo-Tech Tanks
Welcome to the Fish Room | The Stemmed Plants | Mosses | A Livebearer Biotope | Planted Tank Social | The Genus Hygrophila | Cyanobacteria
Easy Plants | What I Did Last Summer | Decorations in the Planted Tank | Botany-An Introduction to Plant Biology | Botany-Anatomy of a plant
Botany-How Plants Work | Easy Rosettes | Going High-Tech | Floating Plants | Dealing with Success | Bringing the Outside In | Vallisneria
Hair Algae | Flowering Aquarium Plants Part 1 | Flowering Aquarium Plants Part 2 | Liverworts in the Aquarium | Elements of Design
Planted Aquarium Maintenance | More Mosses | Invaders | Ferns in the Aquarium | Setting up a Planted Aquarium
Seaweeds of the Pacific Northwest | Proserpinaca | Hardware for the Planted Aquarium | Rotala | Neocaridina Shrimp | Lo-tech Tank Tips

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