How to Take Care of Marimo Balls.




Introduction: How to Take Care of Marimo Balls.

About: I love to make things! I am constantly finding new things to make and do. I love geeky stuff like Sherlock and doctor who.

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.


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.

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!

2 People Made This Project!


  • Tiny Home Contest

    Tiny Home Contest
  • Creative Misuse Contest

    Creative Misuse Contest
  • Water Contest

    Water Contest

150 Discussions

My marimos live in my freshwater aquarium and are browning a little. I want to take your advice and place them in cooler water with ice but will adding salt still be ok if that's not that they are current used to?? Also, is table salt ok?

Is it okay to to get marimo from pet smart? Are they fake or real and how do you tell? Thanks

5 replies

Pet smart sells both types. The real ones are usually back by the live fish; in the same type of container like a beta fish in water. the sku # 073725728340 (Marimo Moss Ball Plant Grab N Go). Some Pet smarts also have them in the tanks with the fish. The fake ones are usually sold in the same isle as the turtle products. (Exo Terra Reptile Moss Ball) item: 5155002

if it eny help to u i got mine from amazon and only took 2 to 3 days then as soon as they arived i rinced them like i was told under cold tap and put then streight in there own water box with a filer i tern on once in a wile to keep the ewarter fresh ope this helps

Not sure about Pet Smart, but Petco has some fake ones(the one where I live anyway).

Some signs it's not a marimo:

1. They are not specifically advertised as marimo balls. IE. If they are advertised as "moss balls", "betta buddies", "fluval", or some other thing.

2. If they are floating. These are sometimes anchored to rocks with string.

3. If they have string tied around them. This is to give them a round shape, which real marimo will have naturally.

Those are ones that I have seen anyway. Though they didn't have them advertised as marimo, they are designed to look quite similar to them. They where also in with marimo balls that weren't marked as being anything different.

Hope that helps a little.

if i get one what floats i put it under the rest lol

1. Will the moss balls do okay in an outside pond in one foot of water?

2. I was told they will prevent other algae. Is this true?


1 year ago

my moss balls turned a grayish color after I put them in my tank, what can I do to get them back to green?

1 reply

From what I understand you turn them over so the other (hopefully green) side is on top.

um hey do you know general pricing on Marimo? I have wanted one for like 4 years now and im ready to get one, any and all help would be appreciated. Thanks!!

2 replies

the pice very from from about a pound each to £5.99 for about 6 on amazon

Amazon, on 4/15/18: (and there are more than 6!!)
"6 Marimo Moss Ball Variety Pack - 4 Different Sizes of Premium...
Sold by:

I've got 8" Oscar's and they like to roll them around, but don't seem to try to eat them. I love these things, I've got them in all 4 of my tanks!

Can you place them with other aquatic plants? If so, what types?

2 replies

they are fine with any other types of aquatic plants as long as they are fresh water. marimos do prefer colder water though so if you were to keep them with other plants in a heated tank, a night in the fridge every once in a while would do them good :)

if it helps i keep mine in room temp warter in kithen its colest place all yr round with a running filter and i take them out every 4 weeks or so and theck them over

my moss ball is turning into a fuzzy ball is that good or bad?