Marimo Moss Ball, or the Japanese Moss Ball as the name commonly used in Aquariums, is a species of Simple plant that grows in water that does not hold any true stems, roots, or leaves and takes the shape of a large green ball a velvety appearance.
The generic name of this plant is Aegagropila which is a Greek name for goat hair. This plant is mainly seen grown in the lakes and rivers of Japan and the Nothern Europe.
Table of Contents
- Marimo Moss Ball Care and Maintenance
- Benefits of Marimo Moss Balls
- Disadvantages of Marimo Moss Balls
- Marimo Moss Ball Care Tips
- How to Maintain Marimo Moss Ball?
- Common Issues of the Marimo Moss Ball
- Suitable Tank Mates for the Marimo Moss Balls
- Unsuitable Tank Mates for the Marimo Moss Balls
- How to Propagate your Marimo Moss Ball?
- What are the Difficulties in Growing the Marimo Moss Ball?
- What are the Difficulties in Growing the Marimo Moss Ball?
This Sea Weed was named Marimo by a Japanese Botanist Takiya Kawakami in 1898, where Mari had the meaning of a Bouncy play Ball, and Mo meant a plant that grows in water.
This plant takes a long period to grow( 5mm per year ) but can retain its life for at least more than 100 years.
So speaking, the size of this plant grows up to 1.75-2.25 inches in diameter, but some even grow up to a foot in diameter.

This plant is found in Aquariums for selling, and mostly one Moss Ball will cost at least around $ 6-$ 8.
The main reason for having such a high price is its slow growth rate.
Marimo Moss Ball Care and Maintenance
Caring for and Maintaining the Marimo is an easy task.
Scientific Name | Aegagropila linnaei |
Origin | Japan |
Lighting Needs | Low |
Temperature | 10° – 28° C° |
CO2 | Low |
Water Conditions | pH: 6.0 – 8.5 |
Average Size | 3-4cm |
Growth Rate | Very slow, only 5 mm / year |
Placement | Foreground |
Difficulty | Moderate |
Water Parameters
Taking Care of a Marimo Moss, you will have to change the water once in two weeks with regular tap water.
If there are very hot days, you will have to change the water more often as it will start to evaporate with the heat. The Marimo is also able to survive without water for a few days if held in a plastic bag or a closed Jar.
Lighting
The Marimo Moss cannot survive its greenness when met with direct sunlight. They tend to change their color to brown when met with direct sunlight.
Therefore they should be kept in a cool place away from direct contact with sunlight.
However, the Marimo has the ability to adapt itself to normal household light. If there is a change of the Marimo into a brownish color, it will change the color back to green by itself when it is changed to a cooler location with less direct sunlight.
If there is still no change in the color, then what has to be done is to add a small amount of aquarium ocean salt to it.
Nutrients and Fertilizers
The Marimo Moss does not require any Fertilizers. Instead, it makes food of its own through the use of Photosynthesis.
If you require to infuse the plant with CO 2, you have to get the original water the plants grew in, put it in a plastic container, and add the CO 2 in it. After that, add the Moss Balls to the Container and allow it to rest for several hours.
Benefits of Marimo Moss Balls
The essential Benefit of the Moss Ball is the requirement of maintenance is less compared to the aquarium plants.
It does not require being anchored like other plants, whereas other plants require the roots to be dug in the gravel or tied to another object where it will be difficult to clean the Container or the tank.
Also, like other plants, the Moss Ball also releases a certain amount of oxygen which will help to oxygenate the tank. Other than that, these Moss Balls also help prevent excess growth of algae in the tank and will not die very quickly.
Disadvantages of Marimo Moss Balls
Apart from the Benefits of the Moss Balls, they also have certain disadvantages like as these Moss Balls takes years in growing, you might have to wait for a while for them to grow, and even though the large balls can be torn to make small ones it will take some time to round them and get the circular shape
Also, these Moss Balls do not reproduce in the tanks like other plants, so you will not find small moss balls lying under the large moss balls after a certain time period like the other tank plants.
Further, like the other tank plant, even if it absorbs the nitrate and produces oxygen, it will be on a very small scale.
Marimo Moss Ball Care Tips
As all plants require care, the Marimo Moss Balls also require some special care. Unlike the other plants, the Marimo should be rolled out at least once a week so as to maintain its round shape.
These Moss Balls roll out naturally when at their natural waters, which help them to keep their shape. But when held in the aquariums, they have no ability to roll around naturally and tend to change their shapes.
Although this change of shape is nothing to worry about, other issues arise, such as the bottom of the Ball being rot. If this rot is not too bad, you are able to leave the plant to recover on its own.
But if this rot goes further and changes its color to a deep or light grey color, that part of the plant should be removed from the green part of the plant and left aside on another part of the tank.
If there is no recovery of this part even after a few days of the time, it should be removed so as to avoid an ammonia spike. Therefore the rolling of the plant is required to maintain its color and beauty.
Although at times this Marimo may seem to be unwell and start to rot and change its color to grey even if the water is perfect and the rolling was done frequently. This happens when the temperature of the water gets over 70 degrees.
You can fix this by taking the Marimo out of the tank and placing it in another water container, and holding the same in a refrigerator overnight. Then take it out in the morning and place it near a window or a cooler area or at room temperature where it is able to receive direct sunlight.
After a few days, there can be seen an increase in the health of the Marimo.
How to Maintain Marimo Moss Ball?
The Marimo Moss Balls tend to accumulate mulm and crud around them. Therefore they should be cleaned every few weeks.
Common Issues of the Marimo Moss Ball
The Most Common issue with a Marimo is the change of its color when the water is too warm or not clean enough, and the light is not optimal.
If these turn into white in color, that means they are receiving too much light, and if there is a color change to grey, they probably need to be cleaned.
Suitable Tank Mates for the Marimo Moss Balls
The Marimo Moss Ball is an attractive plant that is used in the decorating of fish tanks and bowls in the Aquariums. With their fun shapes and movements, they can live with all types of fish.
Still, the perfect fit for the Marimo is the Beta Fish who can live in harmony with them, freshwater shrimps and freshwater snails, however, speaking of the other types of fish that specific species has to be able to survive in water which holds a temperature of between 60-80 degrees Fahrenheit.
Unsuitable Tank Mates for the Marimo Moss Balls
Although it was said that all types of fish could live the Marimo Moss Balls, there is a certain amount of unsuitable fish for a Marimo which try to eat or damage them; among those fish are the Gold Fish, large-sized crayfish, certain types of catfish and some invertebrates.
How to Propagate your Marimo Moss Ball?
The moss ball is capable of reproduction, but as this cannot happen in an aquarium, the propagation of this plant can be done.
What has to be done is to divide the Moss Balls into certain smaller parts and leave them as compact as possible. After a certain period, these small plants will develop their size, and after several reshapings, they will turn into circular shapes.
As these moss balls take time to grow, the growth will be more visible in the smaller ones than the larger ones.
What are the Difficulties in Growing the Marimo Moss Ball?
The moss ball is capable of reproduction, but as this cannot happen in an aquarium, the propagation of this plant can be done.
What has to be done is to divide the Moss Balls into certain smaller parts and leave them as compact as possible. After a certain period, these small plants will develop their size, and after several reshaping’s, they will turn into circular shapes.
As these moss balls take time to grow, the growth will be more visible in the smaller ones than the larger ones.
What are the Difficulties in Growing the Marimo Moss Ball?
The Marimo Moss Ball is said to grow only 5 mm per year, which is one difficulty growing these Moss Balls.
Also, if you are willing to regrow the Moss Balls from the existing ones, the baby moss balls tore from the large ones should always be kept together, then splitting them.
The Marimo Moss Ball is a rare algae that is found growing in a limited area of the water. Because of their appealing appearance, they also serve as a medium for environmental education.
These Moss Balls are created by nature without any human involvement and are considered a plant that brings good luck in Japan.