What is a Marimo ball and How Should I Care For It?

by | Mar 26, 2017 | 6 comments

I bought my first Marimo or what I thought to be a moss ball, a couple of years ago at the pet store when I purchased a fish. It resided in the tank with my beta fish and it lived for a while. I had no idea how to take care of this small green sphere. It disintegrated and I don’t know why that happened. Did the fish eat it? Anyway…….

Try, try again…

I decided to try again. At the same time, I also decided to learn as much about these small green balls as I could. In the process, I found out that they can live for over 100 years. I was sad it had died under my care. So here we go again, and I will do better this time. I bought a new Marimo when I was in the pet store a couple of weeks ago.

Research your plant

I did some research online and found out it isn’t moss. It is a type of algae and its botanical name is Aegagropila linnaei. They occur in cool lakes in Japan and Iceland where they are a protected species. Marimo is a Japanese word that means “seaweed ball” and it is thought to bring good luck. It is a solid ball of algae growing out from the center. In the home, it won’t grow any larger than a 2-3″ ball and is slow growing.

A container for your marimo

I decided not to put it in the fish tank, instead, I found a glass container for it to live in. I have a coffee/tea carafe that Mom gave me years ago that had been in her basement. She said it used to sit on a base with a candle in it to keep the coffee warm. It is Pyrex and she thinks it was a 1957 wedding gift. (P.S. As I write this, I’m at my Mom’s house and I made a sojourn to the basement to look for the stand. I haven’t found it yet, but may look again tomorrow.)

Notice I placed decorative rocks on the bottom, but it isn’t necessary.

Marimo in a Pyrex carafe
Marimo moss ball in Mom’s antique carafe

Marimo Natural Habitat

These algae balls live on the bottom of cold lakes and keep their round shape by the action of the waves. So it is beneficial to swirl the container they are residing in to allow them to move around and keep their shape.

I move the carafe back and forth to get it to roll along the bottom. It is also important that all sides of the ball receive light. If a side never gets light, it will turn brown. They do not need a high light situation, which may burn them, but low to medium light. Remember they are rolling around in the bottom of a lake where there isn’t a high concentration of light.

Marimo Care

Every couple of weeks, change the water. If it is tap water with chlorine, let it sit overnight to allow the chlorine to dissipate.

If your ball floats, it may have an air bubble in it. Squeeze it to remove the air. It should then sink to the bottom. I find these Marimo balls to be so fascinating. If you have a pet or fish store near you, you should be able to find one. If not, you can find them online. I’ll keep you updated on mine and my search for the stand in the basement…..

Marimo in a glass container
Marimo moss ball

P.S. I never found the stand for the carafe but did find a stand for a larger Pyrex container. Also, I had to move it out of the carafe as it was getting too large to be able to get it out. I didn’t want to have to break it, so I moved it to a bowl, which you can see at the top of the page.

Do you have a marimo? How long have you had it? Let me know in the comments below.

Have a great week!

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  1. Matthew steinkopf

    That looks cool.

  2. Angie Rose

    I love these! I have them in my fish tank and my snails love them 🙂

    • thehouseplantguru.com

      How long have you had them, Angie? The one I had in my fish tank kind of fell apart into pieces…..I’m trying again and will am making sure it is moving around once in a while. Thanks for your comments!

  3. Kim Thompson Everett

    oh boy!!!! So cool I have to get one. Lisa, did you get it around us?? I love it.

    • Lisa Steinkopf

      Hi Kim,
      The marimo moss balls can be found at Petsmart or a local aquarium shop. I saw some at Pet Connection at 5 and Middlebelt, but always call to see if they have any in. Thanks, Kim!


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