Marimo Moss Balls – The Earth’s Wonderful and Mysterious Mascot

Marimo Balls or “Rising Japanese Moss Balls” are truly miracles of nature. They are mysterious, beautiful and a great addition to any aquarium tank because they are easy to care for. They are naturally found in regions in Japan, Scottland, Ireland, Estonia and Iowa.

Their more common name is ‘Moss Ball’ however they are not actually mosses.  The scientific names for the Marimo are Aegagropila Linnaei and Cladophora Aegagropila. In their original habitats the inhabitants of the land around the mossballs lakes have their own names for them. The Japanese call them Marimo which translates into bouncy ball (Mari) water plant (Mo).  Native people in their natural habitats they call them “Torasampe” which means ‘Lake Goblin’ and “Tokarip” which means ‘Lake Roller’.*  Fisherman in ireland call them “kúluskítur” which means ‘Muck or dirt balls.’*

The population of the surrounding areas where Marimo Balls naturally exist are well aware of their miraculous beauty and mysterious nature. In their natural habitats they can grow up to 5 millimetres a year. In Myvatin Iceland they can grow up to 12 centimeters and Lake Akai they can grow up to 20-30 centimeters in diameter.*  In some lakes there are sometimes 2-3 layers of Marimo which rotate position in the subtle undercurrent so that they all are able to get sunlight and grow!*

However due to numerous circumstances such as pollution and climate change their numbers are depleting in their natural habitats. In order to protect the Marimo their lakes have been protected since 1920 in Japan and 2006 in Ireland.*

In Japan Marimo are considered a national treasure.* Their similarities to our planet through its spherical shape, need to rotate and lush green color.* In Hokkaido they hold a 3 day festival to celebrate the Marimo and it is said that if you take good care of your Marimo it will make your wishes come true!*

They are balls of Algae and are considered a “floating” plant because it will not attach to anything like a real moss. They need to roll around gently in moving water from undercurrents or filter currents in order to grow evenly to keep their spherical shape. They are not hollow, and grow a rich dark velvety green. They are extremely easy to care for with no need for strong lighting and no need for CO2. They need a gentle squeeze in separated tank water about once a month to clean them. If they are not saturated in water they can float at the top of your tank. Also if they get enough sunlight and pearl enough they can wander off from the bottom of your tank and rise to the top as well.  They can survive almost any kind of water perameters but a temperater of 20-28 degrees Celsius and a pH of 6-8 is usually ideal.

They look very nice in both natural and contemporary styled planted aquariums and especially compliment the dark brown of driftwood. Shrimp and other small fish love Marimo as well because they love to pick at them to feed on microorganisms that live in it. They also inhibit other algae growth because they dominate the fight for nutrients. In regular tank parameters they tend to grow slowly. However, if you dose the water with nutrients, co2 and very high sunlight you can significantly increase their rate of growth and cloning. If you find a Marimo has grown a tumor, that tumor is just a new moss ball growing out of the older one. It will soon pop off and grow spherical on its own. But if you cannot wait for this you can split an existing Marimo into several pieces and these pieces will eventually grow spherical as well and all become separate Marimo. Its pretty much like cloning!

Marimo are great for any kind of tank and any kind of skill level. They look beautiful and are unique and have advantages having them in your aquarium.



* Information on the Marimo’s history and Culture was summarised  from –