Marimo Moss Ball Care: How to Grow and Care For Marimo Moss February 02 2015 96 Comments


Marimo Moss Balls are one of our very favorite plant discoveries of the last few years. Marimo are equal parts bizarre and beautiful, and Marimo moss ball care is very easy.

Marimo Moss Ball Cartoon

Marimo, a Japanese word which literally translates to “seaweed ball” are not moss at all - they’re actually a rare form of spherical algae. There’s no central stone or kernel inside the sphere - it’s solid algae, radiating from the center, growing radially outward at the snail’s pace of just 5mm per year. But in their natural habitats - few fresh water lakes in Japan, Estonia, Iceland, Scotland and Australia - they’ve been known to grow to between 8 and 12 inches in diameter!

Another reason to love Marimo moss balls is beautiful lore that surround these mysterious aquatics. Legend tells of two lovers who desired nothing more than to be together. When their love was forbidden, they fell into the water, and their hearts became Marimo balls. Marimo are said to bring your heart’s desire to both giver and receiver.

And of course, we love Marimo because they live forever. Well, not forever, but easily 100+ years. For this reason, we often joke that Marimo make wonderful family heirlooms.

Marimo moss ball care is quite simple. Here are a few guidelines.

Marimo Moss Ball Aquariums

Light

Keep your Marimo where they will receive llow to medium indirect light. You must protect marimo from the direct rays of the sun, as Marimo can easily turn brown if they are getting direct light! Also keep in mind that direct sun will be intensified by glass marimo enclosures which can heat water quite quickly. Remember - these guys are native to cool lakes, and should be kept cool.

Marimo are well adapted to low light spaces and can photosynthesize in normal household light. If your space has no window, keep marimo close to a fluorescent or full-spectrum bulb.

Changing the Water

Change water once every two weeks using regular tap water (for best results, allow water to sit out for 24 hours prior to changing the water). You’ll need to change the water more often in summer, as it will heat and evaporate more quickly. Clean your marimo enclosure with a brush if algae begins to grow on tank surface.

Browning

If your marimo turn brown, make sure they’re moved to a cooler location with less direct light. They may recover and turn green again on their own. If not, you may add a tiny amount of aquarium ocean salt.

Why are my Marimo Balls Floating?

More than likely, your Marimo balls have an air bubble trapped inside that is causing them to float! Gently squeeze your marimo balls to pop the air bubble. Generally, Marimo will sink to the bottom of their tank within 1-2 days of being added to an enclosure.

Can Marimo Survive Outside of Water?

Yes! Marimo moss balls can survive without water if kept in plastic or a closed jar for several days, as long as they aren’t allowed to fully dry out. Plastic bags are the easiest way to travel with Marimo moss.

Keeping Marimo Shape Round

In their natural habitats, the waves and currents of the lakes gently rotate and roll the Marimo balls along the floor of the lake.

To ensure that Marimo stay keep their round form and don’t flatten out, you’ll want to gently agitate the water in your Marimo enclosure, with the goal that when your Marimo balls settle back to the bottom, they rest on a different side than they had prior. Try to simulate the gentle waves of a lake.

Marimo and Aquarium Safety

Many people ask us if Marimo can go into their fish tanks. We’re happy to report that Marimo are welcome additions to freshwater aquariums. In fact, they naturally absorb toxic nitrates in water and act like miniature filters, cleaning the water.

Though Marimo are safe for your fish, some fish are known to enjoy Marimo a bit too much and may peck at and eventually destroy a Marimo ball. Keep a good eye on things and see how your fish react before you decide to permanently leave Marimo in a fish tank.

Follow these Marimo moss ball care guidelines, and you should see your little guys thriving in no time! Have any questions or your own best practices for marimo moss ball care? Share with us in the comments!