Marimo moss ball care & info

Looking for something to greenify your home that’s a little more unusual than a regular old cactus or tropical houseplant? In search of an original gift?

Let me introduce you to: Aegagropila linnaei, also known as Marimo moss balls. Marimo moss ball care is a breeze and these fluffy green balls are fully aquatic. Perfect for vases, jars or even your aquarium!

Name(s) (common, scientific) Marimo ball, moss ball, Cladophora ball, Japanese moss ball, Aegagropila linnaei
Difficulty level Easy
Recommended lighting Bright indirect
Water Fully aquatic
Soil type None

Marimo moss ball care

Despite what their name suggests, Marimo moss balls aren’t actually made of moss. Confusing, I know.

In reality, Marimo balls consist of a type of algae (Chlorophyta) that grows in a spherical shape because of water currents. They can naturally be found in lakes in cold areas like Japan and Iceland, where they grow in large “colonies” on the lake floor. As with any plant, it’s important to keep in mind the Marimo’s natural habitat if you’d like to keep it indoors!

Luckily lake floors aren’t that difficult to imitate in your home, which means Marimo balls are easy to care for and beginner-proof.

Marimo moss ball light & temperature

Light. Because Marimo moss balls naturally grow on lake floors, they aren’t adapted to direct sun. This means they don’t need much to photosynthesize: bright indirect light works just fine. You can place your Marimo’s container near a window or use a fluorescent plant light to grow it.

Temperature. Again, think of lake floors here. Not the warmest places, so your Marimo moss ball won’t appreciate warm water either. Be sure to keep the water temperature under 25 °C/77 °F to avoid any issues. As expected, low temperatures aren’t much of a problem as long as things don’t get freezing cold.

Marimo moss ball (Cladophora algae) in glass jar | Full Marimo ball care guide.

Marimo moss ball container

Marimo moss balls aren’t picky about their container as long as it has clean water and allows light to pass through.

They are a great option for any unused goldfish bowls you might have lying around (they’re unsuitable for fish anyway, as all species need a filtered aquarium). Other options include anything from a simple glass filled with water to a fancy vase to an old cookie jar. You can even add other aquarium plants or aquarium mosses to make a full aquatic garden.

You can also keep Marimo moss balls in your aquarium. Not only do they add a fun touch, but they also help keep the water parameters stable by absorbing harmful nitrates! Because this particular type of algae is not invasive like some others, you won’t have to worry about a Chlorophyta explosion.

The only things you do have to keep in mind are that some tropical aquariums might be a little too toasty for your Marimo moss balls and some herbivorous fish species will love to consume this yummy alga. Keep it away from algae eaters like goldfish.

Marimo moss ball maintenance

A Marimo moss ball doesn’t require a lot of maintenance, which is why it’s a great option for those of us who don’t have time to water the plants multiple times a week.

All you have to do to keep your Marimo balls happy and healthy is change out their water regularly. Every two weeks or so should work unless a lot of water has evaporated. If there is chlorine in your tap water be sure to leave the new water out for 24 hours so it can evaporate or use a dechlorinator.

Algae growth can happen in a Marimo container, especially if it’s warm and gets a lot of light. You should be able to wipe it off easily enough using a clean sponge that hasn’t been in contact with any chemicals.

Marimo moss ball in glass container on natural wooden pedestal.

Cleaning Marimo moss ball

Your Marimo moss balls themselves usually won’t need to be cleaned, although you can give them a gentle squeeze in clean water to remove any dirt. They do need to be turned regularly. There is no wave movement in a vase, so move them around every week or so or they’ll eventually lose their round shape.

You can also gently roll a misshapen Marimo ball between your hands to get it back to looking normal.

Problems with Marimo moss ball

There are a few issues that might occur if your Marimo moss ball isn’t 100% healthy. Luckily, you should usually be able to save it!

  • Browning. If your Marimo moss ball is browning it might be receiving too little light or temperatures are too high. Increase your lighting if need be. If you haven’t been doing so, move the moss balls around more often so all parts are exposed to the light regularly. If the water temperature is too high, move the container to a cooler spot.
  • Marimo turning white. This can be a sign of too much light. If your Marimo moss balls receive direct sunlight, move them to a more shaded spot. If there seems to be white slimy stuff growing on the moss balls, that’s a type of hostile algae you should remove to prevent trouble.
  • Marimo decaying. If your Marimo moss balls’ care hasn’t been ideal for a long time it might start to rot and decay from the inside out. It will fall apart with parts turning black. Remove any dead bits and try to salvage everything that’s left by gently re-rolling it into smaller Marimo balls.
Marimo moss ball in glass container.

Propagating Marimo moss ball

Propagating a Marimo moss ball isn’t difficult: the moss ball will actually propagate itself!

Although they grow very slowly, small pieces will eventually break off the ‘mother’ balls. If you roll these small bits regularly you’ll eventually have tiny new Marimo balls!

You can also simply break apart a Marimo moss ball to multiply it. The resulting mini Marimos will look a bit wonky at first, but with regular rolling will acquire their typical spherical shape.

Buying Marimo moss ball

Marimo moss balls are extremely popular, so you shouldn’t have too much trouble finding one. Some aquarium stores might sell them, but you can also easily order your Marimo balls online.


If you have any more questions about Marimo moss ball care or want to share your own experiences with this funky algae type, don’t hesitate to leave a comment below!


1 thought on “Marimo moss ball care & info”

Leave a Comment

This site uses Akismet to reduce spam. Learn how your comment data is processed.