The Fascinating History of Marimo Moss Balls (And Why They're Considered a National Treasure)
If you've ever held a marimo moss ball and felt like you were holding something ancient — you were.
These small, velvety spheres have been quietly growing at the bottom of cold freshwater lakes for thousands of years. Long before they became beloved desk companions and windowsill pets, they were forming their perfect shapes in the dark depths of Hokkaido, Japan — rotating slowly in the current, unbothered by time.
Here is their story.
What Is a Marimo Moss Ball?
First, a small and wonderful correction: marimo are not actually moss.
They're a species of filamentous green algae called Aegagropila linnaei and they're one of the few algae in the world that naturally forms a dense, rounded ball rather than growing in sheets or strands. The "moss ball" name stuck because of how they look and feel: soft, deep green, almost velvet to the touch.
They are, however, very much alive. Marimo photosynthesise, respond to light, grow (slowly, but more on that shortly), and release tiny oxygen bubbles when they're happy and healthy. That gentle fizzing you sometimes see? That's your marimo breathing.
They're found naturally in only a handful of places in the world: Iceland, Estonia, Scotland, and most famously, Lake Akan in Hokkaido, Japan. Lake Akan's marimo are unique in that they grow to exceptional sizes and form near-perfect spheres, a result of the lake's particular current patterns and depth.
Is Marimo Alive?
Yes — genuinely, quietly, persistently alive.
Marimo are living organisms. They photosynthesise using light, absorb nutrients from the water around them, and grow continuously throughout their lives. They don't have a nervous system or feelings in the way animals do, but they are responsive to their environment — turning toward light, changing colour based on water quality, and thriving or struggling depending on conditions.
One of the most charming things about marimo is that loose ones in water will actually move, slowly drifting toward light sources over time. It's subtle, and it happens at marimo pace (read: very slowly), but it's real.
In an aquarium or jar, a healthy marimo will occasionally float to the surface when it has collected enough oxygen bubbles from photosynthesis, then gently sink back down as the bubbles release. It's one of those small, easy-to-miss moments that makes marimo owners feel oddly fond of their little companions.
The History of Marimo Moss Balls
Discovery by Science
The scientific story of marimo begins in 1820, when they were first formally described by European botanists. But it was Japanese botanist Takiya Kawakami who gave them their beloved name in 1898 marimo, (meaning "ball of seaweed") after encountering the spherical colonies growing in Lake Akan.
Kawakami was reportedly so struck by their unusual form that he felt they deserved a name that captured their character, not just their biology.
Mari — a small bouncy ball.
Mo — aquatic plant.
Together: something that feels like a small, living toy dropped into the deep.
The Ainu and the Lake
Long before Kawakami named them, the Ainu people of Hokkaido — the Indigenous people of that region — had known and revered the marimo of Lake Akan for generations.
In Ainu tradition, marimo were considered sacred gifts of the lake. The most well-known legend tells of two young people from rival groups who fell deeply in love but were forbidden to be together. Rather than live apart, they fled to the shores of Lake Akan — and at the water's edge, they were transformed. Their hearts became the soft green spheres that still drift along the lake floor today.
Because of this story, marimo became symbols of everlasting love and devotion — treasured, gifted between lovers, and kept as household charms for luck and long life.
This is not a story borrowed or repackaged for modern aesthetics. It is a living tradition, still honoured by the Ainu people today.
Becoming a National Treasure
By the early 20th century, marimo had captured the imagination of Japan far beyond Hokkaido. In 1921, the marimo colonies of Lake Akan were designated a Natural Monument of Japan, one of the country's highest forms of environmental protection.
Then in 1952, they were elevated further still: to the status of Special Natural Monument. A designation held by fewer than 75 things in all of Japan, reserved for places and living things considered irreplaceable parts of the nation's natural and cultural heritage.
To put that in perspective: marimo sit in the same category of protected status as the crested ibis, the Japanese giant salamander, and the ancient cedar forests of Yakushima.
The Marimo Festival: Returning What Belongs to the Lake
Every October, the Ainu people of Lake Akan hold the Marimo Festival (Marimotaisen) — a three-day ceremony honouring the marimo and the lake that holds them.
The festival centres on a deeply moving ritual: any marimo that have washed ashore, been displaced, or are living outside the lake are carefully collected and ceremonially returned to the water. Ainu elders carry the marimo in traditional vessels to the lake's edge, offering prayers and songs before releasing them back to their home.
It is a ceremony about gratitude, reciprocity, and the understanding that some things belong to nature, not to us.
For those who make the journey to Lake Akan in October, the festival is one of those rare experiences that stays with you. The lake in autumn, the ceremony at the water's edge, the quiet acknowledgement of something ancient being honoured.
If the history has sparked your curiosity about what marimo symbolise — the love legends, the gifting tradition, and what it means to bring one home — that's where we began. Read: What Does Marimo Mean? The Meaning, Symbolism & Magic Behind Moss Balls →
Fun Facts About Marimo Moss Balls
They grow about 5mm per year. The large marimo in Lake Akan — some reaching 20–30cm in diameter — are estimated to be over 200 years old. Your Moonling's lineage traces back to something that was alive when the first fleet arrived in Australia.
Their round shape is earned, not given. In the wild, marimo form spheres because gentle lake currents roll them slowly over time, exposing every side to light equally. Nothing grows faster than anything else. The result, over decades, is a near-perfect sphere — a kind of natural geometry that has no shortcuts.
They release oxygen bubbles when they're happy. A marimo photosynthesising in good light will produce tiny bubbles that cling to its surface and occasionally cause it to float. It's one of the small signs that your marimo is thriving.
They can survive remarkable neglect. Unlike most plants, marimo thrive on indirect light, infrequent water changes, and benign neglect. They ask very little. They give back quietly and consistently.
Wild marimo are protected by law. It is illegal to remove marimo from Lake Akan. The ones found in the aquarium and gift trade are cultivated, not wild-harvested — something worth knowing if provenance matters to you.
What Do Marimo Moss Balls Do?
In practical terms: they live, they grow, they photosynthesise, they occasionally float and sink, and they stay green and soft for years with very minimal care.
But in a less practical sense( the sense that most people who keep them would recognise) they anchor something.
There's something about having a living thing on your desk or windowsill that changes the quality of a space. It introduces a different rhythm. You notice it. You occasionally turn it. You change its water every few weeks and notice it seems a little brighter afterward. You find yourself thinking of it as yours.
Marimo don't demand that kind of attention. But they reward it gently, in the way that most slow and quiet things do.
Bringing a Little History Home
If the history of marimo has left you wanting one nearby — we understand completely.
There's something grounding about keeping a living thing that asks so little and grows so slowly. A quiet reminder that not everything worth having needs to be rushed.
Our Moss Moonlings are handcrafted in Perth and paired with an intention crystal chosen for the energy it carries. They're shipped across Australia (excluding Tasmania, due to biosecurity regulations).
