aquarium moss ballToday’s subject is the interesting “Moss Ball” which is a particular favourite in my homeland of Japan. The Aegagropila Linnaeus, also known as marimo, is a class of filamentous green algae known for its distinctive form and even appearance. The Marimo, as I have said, is so popular in Japan we regard it as a National Treasure. Believe it or not, we even give them names and take care of them at home as pets!

The Marimo was initially discovered in 1823 by Austrian Botanist Anton Sauter, in Lake Zeller, Austria and was soon discovered in Japan’s Lake Akan by Tetsuya Kawakami of the Sapporo Agricultural School (now Hokkaido University).

Marimo have not always had a stress-free life in Lake Akan. The lake serves the local area not only as a tourist attraction but as a valuable water supply. The governemt designated the Marimo as a Japanese “Natural Treasure” in 1921. After this people came from far and wide to obtain these distinctive plants. Some were simply removed as keepsakes by visitors. Many others were pilfered and sold for high prices in urban areas.

In 1920 the government built a hydroelectric power plant. It is situated along the Akan River which flows from the lake. The hydroelectric plant used some of the lake water for generating electricity which lowered the water level. As a result, some marimo, which will only survive in shallow water, were left uncovered and withered.

In the 1940s, recognising that marimo was becoming a severely endangered species, the local people launched a campaign to protect them. One of these campaigns still continues today. The Marimo Festival originated in 1950 and is held every October. This is when the autumn leaves on the lakeshores are at their best. This 3-day festival is conducted by the local Ainu people. The festival concludes when an elder, in a small wooden boat, ceremoniously returns the marimo one by one, carefully back to the lake bed.

The local government of Akan re-opened the Marimo Exhibition and Observation Centre in 1996 after a wide-ranging facelift. The new centre is fitted out with numerous facilities to encourage the ecological and scientific significance of marimo. They also conduct important research on the protection and proliferation of this unique plant. The Marimo in Lake Akan can sometimes reach diameters of between 20 and 30 centimetres. We describe these stunning, distinctive living creatures as “jewels of the lake”.

Though Lake Akan is most well-known for marimo, they can also be found in Lake Shirarutoro and Lake Toro near Kushiro’s famous wetland. This area is also known as Kushiro Shitsugen National Park. Marimo also live in Lake Kawaguchi and Lake Sai, two of The Five Lakes of Mount Fuji. However, it is Lake Akan alone that provides such excellent examples of the velvety round marimo.

How Do Marimo Moss Balls Actually Develop?

Marimo will grow in 3 distinct ways. Firstly they can grow on the shady side of the rocks. This is because they cannot withstand high temperatures. Secondly, Marimo can grow free floating and create a carpet on the bottom of a muddy lake. Lastly, they can become just like a ball with compact algal filaments at the centre.

Aquarium Moss Ball

Would you like to create the beautiful sight of the Marimo in Lake Akan? Then why not add some of my exquisitely designed aquarium moss ball to your aquascape. You can view the full range here.

Sayounara さようなら


Hugo Kamishi Moss Ball collection

Hugo Kamishi