If I asked you to say the first plant that comes to mind when you think of Japan, chances are you’d say sakura, cherry blossoms. Sure, they are pretty and they represent the fragility of the human condition and stuff, but I have another much cuter Japanese plant to show you today!

Algae Balls!


Photo by Sendai Blog

These little guys are called marimo. Aren’t they cute? So round! So green! Don’t you just want to touch them? Well I have touched them and I can tell you they feel great. They are all soft and slightly squishy, a bit like wet velvet. The kanji for marimo (毬藻) literally means “ball water plant”. That’s pretty straightforward. They are a species of algae that naturally forms into balls.

The conditions needed to form marimo are incredibly rare. They are only found in Iceland, Scotland, Estonia and Japan. In Japan they mainly live in Lake Akan, in east Hokkaido. The lake has shallow shores, so it provides the conditions needed to form the marimo. Essentially they are just the same as algae you see growing on rocks, except they are free floating. As they grow, they roll down deeper into the lake. This rolling is what gives them their spherical shape. Once they get too deep for the sunlight to reach them they break up and float back to shore. Then they begin their rolling again.


Another interesting trick they can do is floating up and down by themselves. As they photosynthesize they rise and fall in the water. This is why they are sometimes called floating moss balls, even though they are not moss at all. Their scientific name is Aegagropila linnaei. They are also called Cladophora balls or Lake balls. In Hokkaido’s native Ainu language they are called torasampe (marsh monster) and tokarip (marsh ball). Whatever you call them, they are adorable balls – adoraballs!

Algae Bulge?!


Mizumori Amane, the mascot of the Akan Ryokan Association

Marimo’s charm lies in its simplicity. A green ball is a simple icon to turn into all manner of cute goods. You can get all sorts of fluffy green round things to commemorate your trip to Akan, and any number of cute marimos with faces. Since 2013 the Akan Ryokan Association has been promoting itself with a classic anime style girl Mizumori Amane, who is covered in marimo. There is even a kind of marimo jelly. You pierce the plastic skin with a pin and suck the insides out.

But this is Japan, where sometimes cute gives way to creepy. One marimo character stands out (quite literally) from the rest.


This is Marimokkori. His name is a pun, combining the word marimo with the word mokkori. Mokkori (モッコリ) is the Japanese onomatopoeia for something rising under cloth. As you can probably guess from the picture above, I’m being rather delicate with my phrasing. Japan does love a good pun.


Photo by Duke Yuin

Marimokkori is easily Japan’s creepiest mascot. It’s not just his… bulge. It’s that super creepy smile that goes with it. What’s more, he’s not restricted to the adult market. Where you find Marimokkori you will often find kids being amused by him. It’s hard to imagine a character like him being marketed to children outside of Japan. That said, Japanese people aren’t completely blasé about Marimokkori and his round green part. Whether the tourists are Japanese or foreigners the reaction most people seem to have when first encountering Marimokkori is, “???!” followed by laughter.


When he was first introduced in 2005, some people thought the character was a little bit too happy to see them. Several hotels in Hokkaido refused to sell Marimokkori goods in their souvenir shops. These days, he has growing acceptance and appears in many forms; phone straps, boxer shorts, baby clothes, a soft toy where you pull his part that resembles a marimo and he shakes. He has an evil alter-ego Warimokkori. He has a girlfriend who has her bulges in two different places. He has a twitter account. He has a blog. If you live near Sapporo, you can request Marimokkori to come to your old people’s home or elementary school to “bother you.” Marimokkori is on the rise.

But there is more. Mentally prepare yourself for the Marimokkori music video. It was released in 2008 by CORICORI, a band made up of three young boys. It has also been remixed by SMAP’s Nakai Masahiro. Finally there is also an animated version, which you can seek out at your own peril, but I warn you, it includes a whole Marimokkori family.

Algae Blessing


Photo by frontriver

Marimo have been popular for a long time before Marimokkori came on the scene. That popularity has been a mixed blessing. At first it hurt the marimo. Later it helped them and started one of Japan’s first natural heritage conservation movements.

Marimo were designated a Japanese National Treasure in 1921. This actually led to a massive decrease in their wild population as many were removed from their homes and sold to tourists who were now interested in the newly popular spheres. In Tokyo they could fetch prices of around 1000 yen, approximately US$6,165 in today’s money. The marimo in Lake Akan suffered further as logging and the creation of a nearby power plant diverted streams that fed their watery home. The water levels of Lake Akan dropped dramatically and many marimo were left exposed to die on the shore. The power plant at Akan provided the majority of the electricity for East Hokkaido. It was considered a necessary evil until spring 1950, when the plight of the dehydrated marimo was brought to public attention by photos of hundreds of dead marimo.

One of Japan’s first conservation projects was started. The heart of this was the return of the souvenir marimo to their natural home. From all across Japan, people returned the marimo they had bought back to Lake Akan. By the time of the first festival, 48 were ready to be returned to the lake. In honor of these people’s generosity the first Marimo Festival was held on October 7th 1950, with a ceremony to mark the homecoming of the marimo. The festival is still held every October. It involves three ceremonies arranged by the local Ainu people of Akan-kohan, as well as talks on conservation.

However, the connection between the Ainu and the marimo is contentious. For the Ainu of Lake Akan, the Marimo festival draws a large number of tourists. Ainu communities in other areas of Hokkaido have been critical of the marimo festival, pointing out that there are no records or legends connecting respect for the marimo with the Ainu. Indeed, they were a nuisance, getting caught in fishing nets.

One of the “Ainu” legends about the marimo is not passed down by the Ainu themselves, but only by tour guides. It says that the origin of the marimo was an Ainu girl who drowned herself in the lake after her love affair ended badly. Her body became the marimo. This kind of dramatic and romantic legend does seem to have been designed to appeal to tourists.

The Ainu community at Akan has argued back against criticisms that the marimo festival is only a tourist attraction. Mr Tasuke Yamamoto, one of the priests involved in the first returning of the marimo ceremony, said,

“There is nothing wrong in creating festivals, just because they didn’t exist from ancient times. Ancient people made up ceremonious events because they had something important to pray for, which we have surely inherited over a long period of time. As for the Marimo Festival… At first, it was a simple concept of doing a ceremony for the-returned aegagropilas [marimo] to send them back into the lake. But I said, if we are doing it at all, we should respect Ainu worship toward nature, and show gratitude to the ”great nature.”

The marimo festival is part of the complicated relationship Hokkaido has with its native people. The issues of tourism, Ainu spirituality, and conservation all intersect here. If you want to delve deeper into these issues this paper by Irimoto Takashi, published in 2004, is a good starting place.

Where to find your own Marimo


These days the souvenir marimo business is still going strong. However, now the marimo you’ll find on sale in Hokkaido and elsewhere are artificially rolled from free floating filaments, not natural wild marimo. Their sale is monitored by the Hokkaido Fisheries Commission, so that the natural marimo can live in peace, while we can still enjoy their non-wild cousins. The sale of some (though not all) helps fund conservation projects.


Photo by isotope0612

If you visit Akan, you can pick up a marimo from any one of the souvenir shops or lakeside vendors. Even if you don’t venture all the way to Akan, you’ll find marimo in souvenir shops all over Hokkaido. Be aware that taking them back home if you don’t live in Japan may be tricky as they are living plants and could pose a biohazard. You might have better luck with a set of dried starter kit marimo, which are usually sold alongside their damper cousins.


Luckily, you can also get your own little algae friend from aquarium shops in many countries. They will sometimes be sold under the name “Moss balls.” You can also find them at major pet shop or garden center chains. In recent years the price has dropped from around US$20 to about US$8. They are also available in a range of adorably quirky containers on Etsy.

Watch out for knockoffs, which are just plastic balls with a thin layer of algae. True marimo are marimo through and through and if properly cared for will last a lifetime or more.

How to care for your Marimo


Good news! Marimo are almost impossible to kill! Sakura are beautiful for a few days, but a marimo will be your plant companion for life. They don’t ask for much, just water to roll around in so they can get sun on all sides. They don’t like bright sunlight (they come from the murky lake bottom remember), so you can easily keep them indoors. They don’t like chlorine, so keep them in filtered water, or tap water that has been left to stand for a couple of days. You should change their water every few weeks to keep them cheerful.

If your marimo starts to turn brown on one side, just roll it over so that it can get some sunlight all over. Many marimo are sold in round containers in Japan, so that that can be easily swirled around now and then. If the discoloration continues, add a little salt and ice to the water. Marimo don’t mind a little bit of salt. This remedy should have your marimo looking adorable again in a few days.


Photo by mobile_gnome

They are fish safe. Some fish, such as bettas, have even been known to play football (finball?) with marimo. Watch out though; goldfish have been known to eat marimo! Marimo will help keep your fish healthy as marimo purify and oxygenate the water, though they aren’t a complete replacement for other aquatic plants, as they don’t release a huge amount of oxygen. If you are keeping your marimo with fish you’ll want to give your marimo a squeeze every now and then (about every two weeks) to get any gunk out. This will keep your marimo fresh, and you get to squeeze a marimo, which is basically the best feeling ever! Marimo will also help you keep other gross algae at bay by out-competing their non-cute cousins.


Squeezing Marimokkori’s… Marimos

They are slow growing. To get one the size of the largest marimo at Akan, it would take decades. Even to get to the size of a tennis ball can take years. If you want more marimo, you can just split them in half and reroll them into two little marimo babies. Don’t worry about hurting them. Just roll them into shape. While they resemble green tribbles, marimo don’t reproduce on their own (except for gradually getting bigger) so you’ll never find yourself overrun.

And if the thought of looking after a live marimo is too daunting, there’s always the marimo app.

So, that’s the marimo. Easily Japan’s cutest plant, even if it gave rise to Japan’s creepiest mascot. Perhaps it is the simplicity of these soft green spheres that has allowed them to be interpreted in so many ways, much like Hello Kitty’s expressionless face. Still, there’s something strangely cheering about what is essentially a blob of algae.

Note: The author would like to extend her sincerest apologies for any mental scarring brought on by Marimokkori.

Bonus Wallpapers!

[1280×800] ∙ [2560×1600]

  • Gerran C.

    Thanks so much for this post! I loved looking at all the beautiful marimo! :3 I have been wanting to know more about these little cuites after seeing them at my local pet store. With your awesome info, I feel pretty confident about keeping one myself! <3

  • Pepper_the_Sgt

    2 minutes into that video, the scene change comes straight from Marimo’s bulge.

  • Robert Benesh

    These are pretty common in fish stores (at least here). I’ve popped some in all my fish tanks, and they are great for keeping the water clear (unless you have rainbow crabs that eat their weight in them overnight). I had no idea this was anything more. Interesting article.r

  • linda lombardi

    I may have to give up writing for Tofugu now, because I can never hope to equal this.

  • Simi

    I so have to get a Marimo / a few Marimos when I go to Japan this year!!

  • Beetle BANE

    As someone from sect Big Bulges, that Marimokkori is a mascot I can totally get behind! Also, marios in general are pretty darn cute! I might have to fake making one by letting an orange mold. Good job, by the way, writing an article with all the cute, creepy, and historical bits of awesome! You met all my needs~ (You’re missing an image, though. under Algae Blessings. Let me help you with that.)

  • Beetle BANE

    Its a pretty effective transition though. I was pretty entranced from it (though that might have just been the marimokkori-blings the kids were wearing, pretending to be flavor flav time-pieces)

  • orangedude

    They’re pretty dang cute! After checking out the Etsy link it looks like people are selling some baby Marimo in water-containing necklaces, which is pretty awesome if you ask me! I just wonder if they would survive being jostled around and exposed to direct sunlight while being worn…

  • Verity

    Good luck! I hope your future marimo brings you years of joy!

  • Verity

    Cool! Thanks for the tip about rainbow crabs. I’m glad you found the article interesting!

  • Verity

    They are pretty irresistible, aren’t they? I hope you have a good, marimo filled time in Japan!

  • Verity

    Nooooo! That would be a crime against bloggery!

  • Verity

    They are awesome, aren’t they. Perhaps a necklace isn’t the the perfect place for a marimo, but as I said, they’re pretty tough. I imagine they’d be alright, as long as you didn’t take them sunbathing or trampolining with you. Daily life jostling and light exposure would be fine I think, but I don’t know for sure.

    I certainly hope so because having a little marimo to carry around with you would be so sweet!

  • Verity
    This is the animated version. Watch with caution! So much bulge!

  • Verity

    I’m glad you enjoyed the article. For a simple blob of algae marimo are pretty interesting, eh?
    And thanks for the image catch.

  • koichi

    one of those marimos have one too many bulges. Actually, both marimos have one too many bulges.

  • Beetle BANE

    Or perhaps both do not have enough bulges?
    Ponder that bit of jedi wisdom.

  • Beetle BANE

    Oh yeah, totally. I think the first time I heard of them, it really didnt make sense to me why they were so hip, but knowing a little more background and some really silly things that came of it gave me a bit more appreciation for sure. (and no problemo~)

  • linda lombardi

    It’s really annoying that wordpress will only let me upvote this comment once.

  • orangedude

    Awesome! I don’t have a trampoline and I don’t sunbathe, so I’m gonna give it a try! I can’t wait to carry a little Marimo around with me!!! XD

  • demonstrable

    I’m pretty sure this broke my brain.

  • David Andrade

    This is pretty interesting that this article was made, considering I’m doing a homestay in Monbetsu, Hokkaido right now, and I just learned about marimokkori not even a week ago. I first saw the marimo at a souviner shop in the Monbetsu Drift Ice Museum, but at the time my host fathers description left much to be asked, so this article filled all those questions.

  • Verity

    Monbetsu! Giant crab claw? Seal sanctuary? I’ve been there! One of my best friends lives there.
    Marimo and Marimokkori are sold all over Hokkaido, even though they live in only one lake. How serendipitous that you just encountered them!
    I hope you enjoy your honestly in Hokkaido!

  • yoru.morino

    I got the feeling that marimos are pets

  • Verity

    They do seem to bridge the gap between plants and pets! So cute!