Picture of How to take care of marimo balls.
fuzzy marimo.jpg

Cladophora ball "Aegagropila linnae"

A marimo ball is a rare growth form of algae, which grows into large green balls with a soft, velvety appearance.they are native to japan where they naturally grow at Lake Akan. They are also found in Iceland ,Estonia and scotland. They can grow patches on a lake floor at depths from 2 to 2.5 m. The round shape of the marimo is maintained by wave action that turns it.
In Japan the marimo has said to be a national treasure.
They where named by the Japanese botanist "Tatsuhiko Kawakami". Mari means bouncy ball and Mo is a term for plants that grow in water. So , marimo means bouncy plant.People often mistake them for living animals because they are usually moving around in the tank.
I first saw marimo balls when i was looking for an aquarium, then I immediately wanted them!

how to grow marimo balls

Your marimo friends will grow in tap water at room temperature as long as the water is changed every one or two weeks.
The growth rate of Marimo is about 5 mm per year.they grow particularly large, up to 20–30 cm (8–12 inches).

All they need is normal household lighting for them to make food, otherwise, indirect sunlight is fine.
You should turn them over once in a while for them to keep their round shape.
Marimo's are actually VERY easy to take care of, probably one of the easiest plants that live in water.
you just have to change the water once a week and your done!" make sure NOT to have age killer in the water!!!!"
1* They  do not float unless the water is squeezed out of them.
2* They are NOT moss, they are a very unique type of ALGAE.


Unlike the idea that they need little light,  they do best with lamp light especially if you have smaller, rolled marimo.
if so, they will start to grow outward like they do naturally and look very fuzzy.
They do still grow with little light but if you want fuzzy, healthy ones they need light.
[see pic]

Health problems:
If your marimo turns grey then simply flip it over and make sure the grey area gets light.
If that doesn't not work then you can get a bowl, add water, ice and salt, let them soak in that for about 3 hours .

they are a VERY easy plant ( ALGAE) to take care of and are nice for people that want a plant but don't have the time to take  care of it.
They are also a helpfull addition to to fish tanks, thus they act like miniature filters cleaning out the water.

please ask any questions!

1-40 of 67Next »
superpati4 days ago

hi! I have just bought one, and its very little, where can I keep it? in glass or in plastic?

so,no direct sun light? here in Spain it can be quite hot!

thanks and have a great day!

A.C110 days ago

What exactly is "age killer"? I use water conditioner in my tank for the fish, is that okay to use?

Terri-lynC1 month ago
I am new to aquariums and have seen others with these moss balls in theirs n they love them...i see them selling on ebay do you think its ok for my aquarium??
tessia1 month ago

I'm trying to cultivate some marimo from this instructable. I've been trying to find a good water flow to put them in to save me having to turn them, but I'm not having much luck. Originally they were in my main aquarium, which has a lot of current (basically a river tank) but they all ended up stuck to the filter intakes. So now I've put all the baby marimo into a small external filter with clear sides (and Eden 501) and put the filter in a north-facing window. Not much movement so far so I might have to turn them afterall.

tessia2 months ago
I purchased my first marimo ball but it has tiny clear creatures crawling on it and I'm afraid of killing them if I do a water change or roll the ball. What do I do?
neetz (author)  tessia2 months ago
Are they ghost shrimp? They are commonly put with Marino balls.
tessia neetz2 months ago
I think they are. They are very small. Almost can't see them.
Do I want them or not? If so how do I shape, touch or clean the marimo ball or change the water without killing them?

Unless you have fish that might eat them, you can leave them be. They won't do any harm, and as neetz said they are often housed with marimo. Some people run tanks purely for different types of tiny shrimp. My sister used to have a shrimp tank with a variety of them in. They bred, and if you put your hands in the tank they would cover your hands and start to clean them. They were so tiny you couldn't even feel them doing it. Really interesting and kinda fun. :-)

jmhschwanke3 months ago

I have two very healthy Marimo Balls... I've had them for over a year... each lives in their own bottle... and they are healthy green and have doubled in size... a friend sent me a dozen small Marimos for Christmas... they are in a larger separate bottle....however they are not vibrant green... they are a dusty light green...I'm concerned the were frozen in transit...

After reading your advice... I am soaking them in Salt Water for 3 hours and then getting them to a spot where they get more sunlight... I live in Michigan... it's still very cold here... but is there anything else I can do... They're not as "HAPPY" Looking as my other two...

My Healthy two are very fuzzy and very green... where the smaller ones are very smooth... Any other Suggestions????

neetz (author)  jmhschwanke2 months ago
Do the healthy ones get more light?
jmhschwanke3 months ago

Here is my healthy one... in his private bottle..

And the babies... soaking in Salt Water in the Sunlight... :)

Notice how the babies are much lighter and smoother and less fuzzy! :(

Hi my moss ball has a dent inside of her, is she ok?

yes she will be fine just roll her and gently squeeze her every water change the indentation is probably nothing they all come in different shapes and sizes and let her have plant food fluval or seachem work excellently

sheri142 years ago
I have a question please, just bought a Marimo ball.. I keep getting white foamy bubbles that I think may be an algae bloom, My 25 gallon freshwater tank only has two Tetras left but because of favorable conditions for Malawi Cichlids I plan to change over to the African Cichlids, will the Marimo ball be ok for the Cichlids?
CorbinH sheri143 months ago

Do you think the bubbles could have been eggs or some sort of nest? Cichlids have many diverse reproductive patterns including laying eggs in masses of bubbles, or sometimes the eggs themselves look like bubbles. Also, Africa is an entire continent, and most cichlids come from there already (including and most notably the mbuna cichlids you already have; I'm assuming that's what you mean by malawi cichlid). If you're being sold something labeled just as "african cichlid", you really won't know what you're getting and could get stuck with an aggressive species or one with requirements you can't accomodate.

they will be fine just rinse them out every water change and lightly squeeze them out making sure you circulate them around to keep then nice and round and happy they absorb a lot of the ammonia and nitrates and nitrites from your fish also every once in a while it's good to give them plant food like the fluval plant micro nutrients they love it

neetz (author)  sheri142 years ago
I do quite like Cichlids! I think they would do fine with them!
the fish really don't " eat" them if that is what you are worried about:)
they normally just push it around.
I have a plecostomus that I thought would eat it but he likes to play with it!

you can post a pic of the white bubbles if you would like!

please feel free to ask as many questions as you want!!!
hello I have 5 mini marimo balls and 3 bigger one, I just bought them, but I really like them already! in few months I have to go in Italy and I need to bring them with me... how can I bring them? will they be upset if I made them fly twice a year?
thanks, marcella
and how frequently do they reproduce themselves?
do you divided them in pieces or you let them divided by themselves?

let them divide by themselves naturaly the will be all the more happy for it

neetz (author)  marcellahella2 years ago
Hello, I think they would be fine to fly many times a year!
I would put them in a plastic bag with a little water and use a rubber band to keep it closed while there are flying and just put them in an empty jar with water while not.
I do divide mine and roll them so they are in a ball don't have to, ,however, they don't split in half very often but they are very hearty plants!
thanks for your interest!
if you have any more questions just ask!
thanks for the help!
ltan102 years ago
Hi, I just bought my Marimo recently. They are place inside a bottle with a cap. Should I remove the cap off? Also, I notice that some of the green fibers are floating around the bottle already. Is my Marimo in poor health (they are also not floating)?

the fibres just mean there happy as can be

neetz (author)  ltan102 years ago
your marimo are fine! they give off the fibers naturally, mine do that like crazy!
you can keep the cap on as long as you change the water at least once a week.
for them not floating,the truth is that they will usually only float if the water has been squeezed out of them.
your marimo would be brown-yellowish it it was not in good health.

please feel free to ask any more questions!:)
Thank you for replying, it helped ! :D but, in the parcel, wouldn't it recieve no light ??(I'm sorry, i couldn't reply to previous post for whatever reasons..)

there a very hardy plant as they live in the depths of lake akyna in hakaido Japan they will be ok

neetz (author)  Ichigolicioux2 years ago
It would not receive any light but it would not die.

thanks again!

CydneyK6 months ago

Thank you for all the info but I have 2 question I have a female betta fish would it be ok to but the moss ball with the betta?[its only a one gallon goldfish tank] Also I have a moss ball and it produces little white thin strings what does that mean im a little freaked out!?!

You can put a moss ball with the beta, its good for them, i have one with mine and it has little strings coming off occasionally its nothing to worry about just turn it around

cnava1235 months ago
Can you put any type of salt in their water??????
CydneyK cnava1235 months ago

You can put a tbs of fish salt per gallon

but only is there sick

Benji2u CydneyK5 months ago

you shouldn't put "Iodized" table salt into fresh water.. very bad for the fish!! And putting salt into any aquarium should be dissolved first in aquarium water then added slowly into the current. And depending on what you have in your tank will determine the quantity per gallon.. like 1/2 teaspoon per gallon or something like that (example formula) don't dissolve a cup of salt in one gallon of water and add all of it to a hundred gallon tank... do it over the course of a couple of days ect ect

CydneyK Benji2u5 months ago

Benji2u I know my sister made that comment not me shes a little a little know it all.

mmx21 year ago

Hey, i found something round sticking on my marimo's hair, and when I try to take it out i accidentally plucked marimo's hair, I heard from someone that plucking marimo's hair will break their structure, what should I do?

CydneyK mmx25 months ago

u really should

craftraptor7 months ago
Nice! I love marimos and I've always wanted one. Gonna go order some now :)
Marimo71 year ago
Hello, Marimos look interesting to me and I want to get one. I've read that they need to be bathed but I don't know how. Also, do they need to be fed? Please help. Thanks.
Hi! I have some marimo and they turn red all over the outside... Did it ever happen to yours? Do you know why? I can't find nothing anywhere in the internet...Thanks, Marcella.
1-40 of 67Next »