The Ultimate Moss Amigo Marimo Moss Ball Guide

Welcome to the fun world of Moss Amigos! Our marimo moss ball family is based in 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, we provided this detailed, well cited, care guide to ensure you are the best plant parent! 

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 fresh water 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 predictably floating and sinking) that scientists were not able to comprehend for another 100 years. 20th century Europeans saw these moss balls as a merely natural phenomena 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 status as a sacred natural artifact of the indigenous Ainu people. During the first week of every 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 100 years for marimo to grow to their full size
  • Marimo in Lake Akan are by far the largest in the world, growing to a diameter of nearly 1 foot

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 European and Japan where Moss Amigo were originally found, less than 50% are still there. 

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

Care Guide Overview

These furry green balls of joy are actually pure 100% all natural spherical algae. We call them moss balls, but they aren’t actually moss at all, they are pure algae. You might think that there is a pebble or some kind of structure inside the algae, but no. Marimo Moss Balls naturally grow in a spherical shape and consist solely of algae, with no internal object for the algae to grow around. At a breathtaking speed of 5mm of growth per year, you have never seen anything move so fast.

These ancient, legendary plants are a connection to the past. Moss Amigos is giving you the opportunity to be part of an ancient culture. When you purchase a Marimo Moss Ball, you are actually purchasing a family heirloom that will stay in your family for generations.

The natural shape and formation of the algae make for the perfect in home decor. 

But how do you take care of spherical algae? The real question is how do they take care of you! 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 will get larger and larger they will radiate from the center, making them more and more spherical as they get older. It is quite possible that your Marimo Moss Balls 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 first tip you should remember when caring for your ancient pet plants is to keep them out of direct sunlight. Finding the perfect amount of sunlight for your Marimo Moss Balls is a piece of cake. When the spherical algae balls are getting too much light, they develop white specs. This is your signal to put them in an area with less sunlight. If they are showing signs of developing a brownish color, then they are not getting enough sunlight. 

Don't think too hard about this. Just find a space that isn't directly in the sunlight, and not tucked away in a crevice and you will be fine. Your new friends will suck up all the vitamin D coming from the ambient light that finds its way over to its living space. 


Change their water every 2-3 weeks. (filtered tap water is best) Keeping the quality of water suitable for your moss ball is critical. If you have fish, your normal schedule of changing the water will be perfect for your Moss Amigo. Keep in mind, because marimo moss balls suck up nitrates and other nasties, your fish tank water will look cleaner and clearer for longer than you are used to. Just an added bonus.


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


The Moss Amigos (Amigos = Friends in spanish), act as your avenue to experience true Japanese design. We are bringing these minimalist art forms into your house for you to appreciate the subtleties in the structures of nature. Our round, green, and fuzzy friends will absorb your vibes and channel a consistent stream of positive energy.


Well, there you have it. We know your probably rushing out to find your very own Marimo Moss Ball right now. Don't forget that the Moss Amigos are your #1 source for premium quality Marimo. See you soon!

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