The Ultimate Moss Amigo Guide

Welcome to the fun world of Moss Amigos! Our marimo moss ball family is based in Northern California and all of our Moss Amigos are sourced domestically in the United States. Although our little green friends are extremely convenient to take care of, they are still living organisms, so we want to provide this simple care guide to ensure you are the best plant parent possible! 

Historical Context

Acton E . 1916. On the structure and origin of “Cladophora balls”. New Phytologist 15: 1–10.

Marimo moss balls are historically found in the cold freshwater lakes of Northern Europe and Japan. The first English language documentation of Moss Amigos was in 1916, by scientist Dr. Elizabeth Acton. They are known in the European scientific community as “cladophora balls.” Initially, they were noticed more prominently in Scottish and Irish lakes; however they were also found in different places in Northern Europe as well.

Even though there was a basic grasp on the anatomy of this curious plant, they would exhibit interesting behaviors (such as unpredictably floating and sinking) that scientists were not able to comprehend for another 100 years. 20th century Europeans saw these moss balls as merely a natural phenomenon and there is no documented cultural reverence for our little green friends.

In Japan, they are known as "marimo" and are a protected species because of their high status as a sacred natural artifact of the indigenous Ainu people. During the first week of each October, they hold a three day festival as a way to protect the marimo and honor the environment. 


Some facts about the marimo in Japan:

  • Volcanic activity formed Lake Akan 6,000 years ago.
  • It takes up to 100 years (!) for marimo to grow to their full size, typically growing at a rate of about 5mm per year.
  • Marimo in Lake Akan are by far the largest in the world, growing to a diameter of nearly 12 inches.

Unfortunately, marimo moss balls have been disappearing from over half of the lakes all around the world. According to the American Institute of Biological Sciences, scientists found that across the 238 lakes in Northern Europe and Japan where these moss balls were originally found, less than 50% remain. 

To respect these traditions and the natural environment, our Moss Amigos are carefully cultivated in the United States.

Care Guide Overview

These furry green balls of joy are popularly known as moss balls, when in fact they aren’t technically moss at all, but pure 100% spherical algae. You might think that there is a core or some kind of firm structure inside the algae, but in fact, marimo moss balls naturally grow in this spherical shape and consist solely of the algae, with no internal object for the algae to grow around.

These ancient, legendary plants are a connection to the past, and Moss Amigos is giving you the opportunity to share in this ancient culture. When you purchase a marimo moss ball, you are actually purchasing a family heirloom that could easily stay in your family for generations!

The natural shape, formation and color of this algae make for the perfect accent in home decor. 

But how do you take care of spherical algae? Simple - just let it be! Marimo moss balls require so little maintenance that if they weren’t so darn cute, you might forget you even had one. No need to have a green thumb with these babies. Strap on your independence helmet, and live your life free of any plant responsibilities.

As the algae gets larger they will radiate from the center, making them more and more spherical as they get older. It is quite possible that your amigo might live longer than you. In fact, the world's largest Marimo Moss Ball is over 200 years old! In the right conditions, these spherical algae balls can live through generations and be passed on through family lineage. Learn more about the Japanese legend that is marimo moss balls here.



The main tip you should remember when caring for your fuzzy companion is to keep them out of direct sunlight. Finding the perfect amount of light for your Marimo Moss Balls is a piece of cake. When they are getting too much light, they will develop white specs; this is your signal to put them in a more shaded area with less sunlight. If they start to develop a brownish color, then they are not getting quite enough sunlight.

Don't think too hard about this. Just find a space that isn't directly in the sun’s rays, and not tucked away in the darkness or under artificial light and your fuzzy friend will thrive. They will suck up all the vitamin D coming from the ambient light that finds its way over to its living space. 


It’s recommended to change their water every 2-3 weeks using filtered tap water. If you have fish, your normal schedule of changing their water will be perfect for your Moss Amigo. Keep in mind, because marimo moss balls suck up nitrates and other dirty particles, your fish tank water will actually look cleaner and clearer for longer than you are used to - an added bonus!


Keep your buddy cool! Don't let them get too hot during the summer, especially since things can heat up pretty quickly during this time. If you have found the optimal spot for your moss ball, then this won't be a problem for you. The natural habitat of the algae is in fresh, cool water. For our purposes, normal room-temperature water will be suitable for a long and healthy life.


Your Moss Amigos act as your avenue to experience true Japanese design. We are bringing these living minimalist art forms into your house for you to appreciate the subtleties in the structures of nature. Our bright and fuzzy friends will absorb your vibes and channel a consistent stream of positive energy. And anyway, who doesn't love a little pop of color in their life?


Well, there you have it. We know you're probably rushing to order your very own Marimo Moss Ball as we speak. Don't forget that Moss Amigos is your #1 source for premium quality Marimo. See you soon!

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Frequently Asked Questions