Aquarium mosses – All You need to know

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Mosses are a popular addition or even a base in many aquarium arrangements. Due to certain properties, they are used by both beginners and advanced aquascapers participating in international competitions. What is it about mosses that makes them suitable for such a wide range of tanks?

They definitely have a lot of charm. Thanks to their small leaves, they create quite compact structures that can often be sheared like hedges. By the way, they thicken with each cut. Among other things, this property of mosses, combined with their low requirements, allows us to integrate them into any aquarium.

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What should you pay attention to when choosing mosses for your aquarium?

First of all, let’s pay attention to the size and growth rate of the moss that we want to apply. Some mosses, such as ‘Peacock’, ‘Java’ and ‘Willow’, quickly grow to quite large sizes. Therefore, when placed in a small aquarium, they would quickly dominate it, filling the entire free space. It is acceptable and often used, for example, in breeding aquariums. In them, small fish or shrimp use clumps of moss as a shelter. Otherwise, this process is inadvisable as it takes up valuable swimming space and makes it difficult to observe aquarium creatures. Going back to the size of the moss, the size of the clump is of course adjustable with care treatments. In this way, professionals maintain beautiful and natural-looking bonsai trees or even lawns in their arrangements. However, you can make the task easier by choosing the right species. For example, in a small tank or for fine details, instead of using the larger ‘Christmas Moss’ use ‘Brasil Moss’ which has a similar structure but creates smaller clumps.

Aquarium mosses can be the basis of our arrangement
Aquarium mosses can be the basis of our arrangement

So what should you know before you decide to buy moss for your aquarium

At the start, a little bit about the form. While it may differ from species to species, there are a few general rules that help us deal with mosses in the aquarium more easily. While other plants are simply planted in the aquarium in the substrate, mosses have their own rules. Of course, you can put a clump of moss in some litter and it’ll probably even grow over time, but there are better ways to do that.

So you buy moss. The most optimal form is to buy a clump or in-vitro culture in a cup filled with gel or water with fertilizers. Why? Because there is simply the most of it. Mosses, unlike some plants from in-vitro breeding, have never been a problem for me when acclimatizing in the aquarium and switching to the underwater form. Armed with moss and a vision of its growth in the aquarium, we go to work. The easiest way is when we want to make a “tree” arrangement, then we have a base (root) to which we attach the moss. This is best done outside the aquarium to ensure good access from all sides. During work, make sure that the moss does not dry out by sprinkling it with water every now and then. Lay the moss flat on the surface you are about to cover. It makes no sense to lay down several layers. Those deep underneath will not have access to light and will rot quickly. Fastening moss to a root or stone is usually done by attaching it. I recommend thin fishing lines with which we tie “ham”. Some people use cyanoacrylate gel glues for fixing. Personally, I do not like this method, because it is very easy to overdo the amount of glue and “drown” the moss in it. This ends up destroying the plant. So let’s get a bit of trouble with the bonding, leaving the glue possibly for the occasion of sticking large clumps. If you are concerned about the line becoming too visible, don’t worry! In about a month, you’ll be able to remove it as soon as the moss grows to the root.

How do you anchor the moss?

There are several ways to do this:

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  • the already mentioned binding it on wood
  • fixing on stones, lignics, etc.
  • tying on pieces of coconut, bamboo
  • binding on ceramic ornaments (tips, tubes, etc.)
  • sticking small tufts of moss into gaps or between stones
  • inserting tufts into the substrate (preferably active).

Moss requirements

In addition to the shape and target size, there are a few more things to pay attention to when choosing the right species for your aquarium. Mosses have an amazing ability to adapt to conditions. They grow both with high and low light intensity, in aquariums fertilized with a complete set of elements and CO₂, and in those where no one ever spills any “chemicals”. The relationship between the conditions and the growth rate or the shape of individual twigs has so many variations that it will be difficult for me to describe them here. It’s enough to mention that even the most popular mosses can sometimes bend trappers when identifying them on various internet forums.

Basically, mosses look “book-like” in good light and fertilization. They also have quite large growths, which at first makes us happy, but over time means that we have to trim them every week or two. Supposedly nothing, and yet … The necessity to trim the moss in a pampered arrangement keeps many scissors awake at night. The cutting itself, however, is not a problem. The problem may be what we cut and fall to the bottom … In a beautifully well-kept lawn … Wherever it should not be. Unlike other aquarium plants, mosses sink. Therefore, we cannot collect the cut-off pieces with a net from the glass, and that’s it. You have to pick them carefully, otherwise our lawn will sprout with new, unwanted clumps every bit. Therefore, wherever possible, I recommend placing the moss on moving elements, such as a root or a stone, which we can easily take out to the bowl and cut without having to play in catching pieces of moss from other plants. This makes it much easier to work and shape shapes later.

With mosses on the elements of the arrangement, even if you do not plan to trim them, it is worth taking them out from time to time and rinsing them in the water from the substitution, because as dense and compact, they collect a lot of pollen.

Mosses, due to their form, will give character to any arrangement
Mosses, due to their form, will give character to any arrangement

Mosses and algae in the aquarium

Another common moss problem that occurs in aquariums is the algae. Especially threads and red algae can grow so much in clumps of moss that it becomes a dubious ornament. Then the best solution is to improve the water conditions in the aquarium. Algae are manageable, but it requires knowledge (water tests) and work (fertilizers, replacements, keeping the aquarium clean).

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The worst way to get the algae in the moss is the so called: mower fish (Siamese algae-eater, Crossocheilus oblongus), known for their algae-eating nature. Why the worst? Because even when we have an aquarium large enough for them, most often moss, as a soft, small-leaved plant, finally enters their menu. You can’t fool nature. Somewhere in the middle of this struggle there are preparations like “Carbo” or others called “liquid charcoal”. This is not a bad solution, but the use of shock doses, usually overdosing Carbo four times, often ends up burning the moss that we want to save. So if you reach for these types of measures, prepare for a longer, calmer process of gradual disappearance of algae at normal doses rather than their magical disappearance.

I will not write about individual species here – all mosses are very graceful and easy to breed. Individual species may, however, drastically differ in terms of optimal water requirements, but it is worth taking the risk and putting them into a slide. For example, Polish spa (‘Willow Moss’) feels best in cold water with high flow, yet it often ends up in aquariums with poor filtration and warm water, giving beautiful visual effects.

article and photos thanks to Małgorzata Achtelik from

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Animal at home is a project derived from the Polish portal dedicated to domestic pets, which I run. This blog category features the best articles I have created with pet experts. Together, we help educate their current and future owners.

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Jakub Markiewicz
Jakub Markiewicz
Hi, I am the author of the blog and series of thematic portals since 2013. I have nearly 15 years of experience in working in the media, marketing, public relations and IT. If you are interested in cooperation, you would like me to write about something or test a product - let me know.