How to grow mosses in the aquarium

Introduction

There is a very wide variety of mosses that grow well in aquariums. The most commonly available species is probably Java Moss (Taxiphyllum barbieri). Other common mosses in the aquarium trade include

Christmas Moss (Vesicularia montagnei) 

Anchor Moss (Vesicularia sp Anchor moss)

Weeping Moss (Vesicularia ferriei)

Flame Moss (Taxiphyllum sp Flame moss)

Taiwan Moss (Taxiphyllum alternans)

Fissidens fontanus

Fissidens crispulus

Often included in this discussion are Riccardia chamedryfolia and Riccardia graeffei, which are actually liverworts rather than mosses, but tend to be grouped with the mosses as they have similar uses and growth requirements. There are many other mosses of interest to collectors, but they may not appear regularly in the trade.

How is handling mosses different from other aquatic plants?

All mosses are handled in a similar way, although they can have different growth forms. There are a few aspects of mosses that make them very different from normal aquarium plants.

Firstly, they are very hardy and have lower light, CO2 and nutrient requirements than other more demanding aquarium plants. Mosses (almost all species) are almost indestructible in most tanks as long as the tank has clean, filtered water and stable parameters. Unstable parameters and poor water quality can cause mosses to melt or slowly deteriorate over time.

Mosses generally prefer lower temperatures and may not do well in warm tropical tanks where the temperature rises above 28 degrees Celsius. They are best kept in cooler tanks below 26 degrees Celsius. At higher temperatures most species will still grow, but their form will not be as compact and the colouration may be more yellowish than green.

Mosses are also susceptible to algae - and this is the main reason why many planted tanks fail to maintain beautiful moss. While mosses themselves have very low requirements to grow and survive, keeping the tank free of algae to display them beautifully is another challenge altogether. It is this aspect that limits their use in the hobby, although most mosses can grow in most tanks as they can survive in an extremely wide range of parameters with low requirements for light, CO2 or nutrients.

Java moss is by far the most hardy of the mosses, it can grow in much warmer temperatures and tolerate poorer water quality.

The slower growing liverwort Riccardia is probably the most finicky species on this list. To get it into good shape, it does best with CO2 injection, cooler water and regular nutrient doses.

All aquatic mosses will naturally adhere to hard surfaces over time and do not require substrate to grow. Large clumps of moss can be grown directly on the aquarium substrate, but the most common way to use moss is to 'paint' rock and wood surfaces. This allows the moss to take on the contours of the hardscape, giving the rock and wood a naturalistic aged look. As moss prefers a stable environment to propagate, it is ideal to attach it to hardscape where it will remain permanently.

Moss can be propagated from the smallest fragments. Larger strands of moss can be cut into smaller pieces (0.5 to 1cm) and these smaller strands will grow out. Longer strands can be broken into smaller pieces before application to give an even coating when applied to hardscape.

Key success factors:

• Clean filtered water

• Stable environment, with no large shifts in parameters

• Tank environment that does not have frequent algae outbreaks

• Cooler temperatures (26 degrees celsius and below)

• Minimum lighting required (mosses can still spread at as low as 10 umols of PAR)

Attaching mosses to hardscape

There are several methods of attaching moss to hardscape. One conventional method is to tie it in with fishing line or cotton thread. Thread is easy for most hobbyists to work with. Large pieces of moss are cut into more manageable lengths (about 1-2cm) and then wrapped around the wood/rock surface with thread.

A newer method of attaching moss is to use superglue. This method requires a little more practice, but gives more precision when planting specific small areas. It is also much quicker. Using gel type superglue (make sure it is ethyl cyanoacrylate), apply a drop to a fingertip sized sample of moss - then press the moss against wood or rock and hold for 15 seconds before releasing. Superglue will leave white glue marks on the hardscape, but these will be covered by the moss in time. They can also be scraped off by hand.

Trimming &propagation of moss

Moss can be propagated from very small fragments. You can cut off moss just like giving someone a haircut. The pieces can be reattached to other areas and new patches of moss will grow. This has both advantages and disadvantages. The pro is that the moss is really easy to propagate. The downside is that all those little pieces you miss when you are trimming will create patches of moss wherever they land - as long as they have access to light. This can smother slower growing species such as Bucephalandra.

When trimming moss, you can use a siphon with a net at the end to catch the moss pieces.

Algae on moss ?

Moss is very susceptible to algae infestation. The fine texture of moss can make it difficult to remove algae manually. Moss can also be sensitive to algicides. The best method is to cut off the top of the algae-infested layer of moss and allow the bottom to regrow. However, this will only work if the moss has favourable conditions for regrowth - you must also ensure that the algae do not continue to spawn, otherwise the problem will persist.

Having conditions that allow the moss to grow robustly and out-compete the algae is still the best way to have algae-free moss. This is where CO2-injected tanks have a huge advantage, as moss grows faster and more robustly when CO2 is readily available. In such conditions, moss grows rapidly and removing algae infested growth - allowing clean portions to regrow - is an easy solution.

Reducing algae triggers in a planted moss aquarium

• Moss requires very low light levels to grow; use less light in tanks where there are no light demanding plants

• Removing of organic waste is paramount; do light substrate surface vacuuming during water changes to remove organic debris. Link here to see how it should be done

• Large and regular water changes (say 50% weekly) are great for maintaining water quality

• Tanks with lower bio-load are less prone to algae - do not over feed. Stock lightly at start to allow the system to build up biological filtration capacity

• Have adequate flow in tank system. This will prevent debris build-up on moss patches and carry detritus to the filter system. 6x-10x filter turnover rate is a good number to aim for. (A 200L tank running on a filter that does 2000L per hour will have 10x turnover for example)

• Use CO2 injection to give plants/mosses a growth advantage. This can be very significant.

• Shrimp/SAE will eat some types of algae, but are not a complete solution in the long term. SAE may also eat some mosses.

Examples of using moss in aquascapes

Moss is an ideal decoration for smaller tanks. In this top view of a 9 gallon tank, many different mosses are glued to wood to create a range of different textures. The front of the tank is shown below:

In this 9 gallon tank, moss is used to fill out the foreground and hide connecting seams between the rocks and wood.

Moss used give a naturalistic and aged texture to hardscape.