What’s round, green, fuzzy, and surprisingly beneficial for your Betta fish tank? It’s the latest trending aquarium must have, marimo moss balls. These eye catching balls of green do more than just add colorful appeal to your fish tank. They are, arguably, the lowest maintenance live plants available.
Natively found in lakes in Austria, Japan, Iceland, Scotland, Estonia, and Australia, these balls are not actually moss at all; they are a type of algae. They were named “marimo” by Japanese botanist Tatsuhiko Kawakami, deriving the name from the Japanese words “mari” for toy ball and “mo” for aquatic plant. Domestic marimo are a perfect match for the temperature range of Betta fish tanks, which are ideally kept between 78 and 80 degrees Fahrenheit. Aside from keeping water at a reasonable temperature, these balls require little other care. Room lighting is more than enough to fuel their photosynthesis needs and a regularly maintained water change schedule, which is needed anyway for healthy aquarium maintenance, is all the other care needed for their health. An occasional squeeze to clean them is the only direct interaction they ever really need. No fertilizers, special soil, or added plant food is demanded by them, making this species a very desirable live plant even for those who do not maintain a naturally planted aquarium. Take a look at this video by user CheemoBettas to see how a marimo moss ball looks in a Betta tank.
I personally love how they look and how easy they are to care for. Any live plants are better than no live plants, so they certainly have suited me during my low-budget aquarium days and were simple enough to make them hassle free. Of course, watching how my Betta fish interact with them is a reward in itself. My Betta fish, who notoriously enjoy squeezing into tight places when hiding or exploring, enjoyed inspecting this new addition to their tank. Unlike the harmful plastic plants that are often pushed in pet shops, marimo moss balls will not tear a betta’s fins nor will one need to planted within gravel. Marimo can sit right on top of any substrate you have, leaving plenty of options for strategic decoration possibilities. There are few negatives to adding one or more of these plants to your fish tank. The greatest benefit, however, is that as a live plant they help keep water conditions healthy and remove nitrites and nitrates from the water.
Marimo can also easily be bred, so to speak. A larger marimo can be cut in half and reshaped back into a healthy ball while its split half can grow into a separate plant. This is another fun part of owning this plant. It is important to research the proper steps in duplicating your moss balls before trying this out yourself.
One potential negative is that upon arrival the ball may become flattened from shipping but luckily this is a quick fix. Some wild marimo become flat in their natural habitats too, depending how they are situated in their environment. Just as may be done to clean the marimo, a gentle squeeze and reshaping is usually all the ball will need to regain its shape. Marimo are also available in a variety of sizes but buyer beware, what you pay for is not always the size you ultimately end up with. Larger marimo are actually aged plants. It is usual for them to grow 5mm per year. This isn’t much as it typically takes about 20 years for the balls to grow 3cm, though certain conditions may cause accelerated growth. Older marimo tend to cost more because they are significantly older than their smaller brethren.
If you are considering a live plant for your betta tank, but are worried about care commitment, this one is a must to consider. There are fake marimo out there, so before purchasing make sure what you will receive is authentic and not a synthetic plant. If you would like to add these beautiful balls to your Betta fish tank, you can purchase a large 2 inch marimo with a bonus smaller ball here and a set of five small half-inch balls (plus one bonus) are available here.