Caring for Marimo Moss Balls

Marimo Moss Balls are rare algae growths that only form in a few lakes in Iceland, Scotland, Japan and Estonia. Many cultures consider them to be good luck and treat them almost as pets (you can think of them as the aquatic equivalent of a "Pet Rock"). These happy little plants will live in containers and are very easy to care for.

However, we do recommend a few care guidelines to make sure your new friend can live its best life:

Containers and Placement

Marimo Moss Balls should be placed in a container filled with cold tap water that is changed every 1-2 weeks. You may place living or decorative elements inside the container, but make sure to rinse them beforehand to remove any potential dirt or other contaminants. Common elements include brine shrimp, betas and freshwater plants.

The container should be placed in a low light situation. Marimo Moss Balls typically live on the bottoms of riverbeds, so they are not used to direct sunlight and will not tolerate it well. Depending on the amount of oxygen produced during photosynthesis, your Moss Ball may float off the floor of the container. They will not require food or fertilizer of any kind.

Ongoing Care

The beautiful round shape of Marimo Moss Balls is formed by the gentle lake currents. To simulate this at home, simply swirl the water around in the container from time to time. You can also remove the Moss Ball and gently roll it against your palm to form a nice shape.

Problem Signs

If your Marimo Moss Ball starts to turn brown, you should remove it from the container, replace the water and squeeze the Moss Ball under running tap water to remove any dirt or debris. The addition of table salt (roughly 5%) to the water can also help, as will a night in the fridge (they prefer cold water).

Your Marimo Moss Ball should recover quickly. These fascinating specimens are very resilient and have been known to live for up to 200 years and will grow 0.5 cm a year.