Why Is My Marimo Moss Ball Turning Brown?

Marimo Moss Ball or the Japanese Ball is a God given gift of nature. This is a form of Algae found in the lakes and the rivers in Japan and the Northern Europe.

Why Is My Marimo Moss Ball Turning Brown
Why Is My Marimo Moss Ball Turning Brown : Image Source

The Japanese treat these Moss Balls as a charm which bring luck to their life and with the life span of a Marimo Moss Ball being over 100 years, the Japanese pass these Moss Balls from Generation to Generation.

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They even treat these Moss Balls as Pets with their smooth, funny and fluffy look and handover these Marimos as pets to their Children. Unlike other types of pets, the main reason to hand over their children with the Marimos is their requirement of low maintenance.

But Nowadays other than a pet people all around the world, not only in Japan use this Algae as a decoration to their Aquarium. This Algae is now a famous and a mostly used decorator in Aquariums.

Although it is said the Marimos require Minimum Maintenance, the Marimo Moss Balls has its own disadvantages.

Marimo Moss Balls are green velvety Balls, so to have this green look in them they have to receive the required amount of sunlight, a cool tempered and clean water.

The Lakes or Rivers in which the Marimo Moss Balls are naturally grown is cold in temperature and the Marimos do their best in these Waters. They receive the required amount of sunlight and through the waves in these lakes and rivers get the required amount of cleaning to their Moss.

But this situation changes when moved to an Aquarium, here they should be provided with their requirements at the Aquarium.

If you are not careful on the Maintainance of these Moss Balls there are certain health problems that can occur which might even cause the Marimo Moss Balls to die.

Marimo Moss Balls are beautiful in look and also high in their price with their low rate of growth.(which is 05 mm in diameter per year).

So it will be a waste of time and your money if the proper look into your Moss Balls are not given.

Why is my Marimo Moss turning Brown?

Marimo Moss Balls change their green colour to a totally different colour of Brown when not given the proper care.

The Cause of this Brown colour is due to the holder or the tank in which these Marimo Moss Balls are kept is not clean enough to them.

Therefore you will have to clean your Marimos thoroughly.

Why is my Marimo Moss Ball turning Uniformly Brown?

Health problems of the Marimo Moss Balls can be cured very simply.

A Uniform Brown change of the Marimo Moss Balls means that the Marimo Moss Balls are getting dirty and needs to be cleaned as soon as possible.

When your Marimos are Brown in colour what you have to do is to take the Marimo Moss Balls out of your tank and give it a proper cleaning using dechlorinated/ purified tap water or bottled aquarium water.

If the first step of cleaning does not work and your Marimos are still brown in colour , you have to dunk these Moss Balls in the water lift them, squeeze and swish in a manner which will not harm these Moss Balls.

If both the above 02 steps do not work and your Moss Balls are still brown in colour, you can take a container add a pinch of salt into it and leave the Marimos in it which will help the Marimo Moss Balls to gain its green colour back.

Why is my Marimo Moss Balls Brown on One Side?

Sometimes even if your Marimo Moss Balls does not totally change brown in colour.

There are times where only one side of your Moss Ball turning Brown in colour.

This might mostly be seen on the Bottom of your Marimo Moss Balls.

If there is only one side of your Marimo Moss Balls changed in colour, then that means that side of your Moss Ball is not receiving the sufficient amount of light to it.

You can fix this problem by moving your tank or container to a place which receives enough sunlight .Turn them around so that each part of the Moss Ball receives the required amount of light.

If your tank or container is not close to a window, the aquarium light or the light at your house is enough for the Marimo Moss Balls.

Keeping the Marimo Moss Balls with the enough amount of light will help them to gain their green colour back on them.

Why is my Marimo Moss Balls White or has White Spots?

As Marimo Moss Balls change their colour to Brown only on one side of them when they are not receiving the required amount of light , they also tend to change their colour to white when they receive too much of sunlight on them.

Therefore you should be careful when providing your Moss Balls with Sunlight.

Keep your tank of Moss Balls in a place that it receives sufficient Sunlight but not too much of direct Sunlight.

Direct Sunlight or too much of light will increase the temperature in your tank or Moss Ball Container.

As Marimo Moss Balls require a cool temperature in their water, keep your tank in a place where it does not receive direct Sunlight.

If you are using an Aquarium light on your Moss Balls which is too bright try to dim it or use a lamp with less light or other than that you can also use other plants in your Aquarium to provide a shade on the Marimos.

If that is also not possible move your Marimo to another tank or container.

This problem should be fixed as quickly as possible or otherwise too much of light might even kill your Marimo Moss Balls.

Also at times you might see that your Marimo Moss Balls might have some white spots on them, this might be due a parasite attack.

You can overcome this problem by cleaning your Marimo Moss Balls as best as you can.

You can move the Marimo to another container with fresh water by cleaning.

You can dunk the Moss Balls in water and give them a gentle squeezing.

So that they get cleaned and you can leave the Marimos in a clean brackish water container and have it there until the parasites are removed and the Moss Balls turn themselves green in colour.

Why is my Marimo Moss Balls Slimy Green?

Same as with the attack of parasites, they might sometimes be attacked by other types of Algae which might cause the Marimos to turn slimy or grow a layer of something around its surface.

Same as with the parasites attack you can change your Marimo Moss Balls to another container with clean water dip them in water squeeze them, have them in clean brackish water until these invasive Algae are fully removed.

This growth of Algae on your Marimo Moss Balls should be treated as quickly as possible or they will invade your Marimos and kill them after a certain period of time.

So other than cleaning the Marimo Moss Balls and making them healthy you will also have to keep your fish tank clean by reducing the amount of food that you feed your fish and clean the substrate to remove the waste buried in it at the bottom of the tank.

Why is my Marimo Moss Balls Black?

Marimo Moss Balls in your tank turning black might be a serious issue. This means that your Marimo Moss Balls are dying or decaying.

The cause to this situation might be that one of the below damages which was caused was not dealt with properly by you.

It could be either unclean water holding the Marimos for a long time period. Too much of direct sunlight for the Marimos for a long period of time. Less amount of Sunlight received on them. Attack by Parasites or other Algae for a long time without being dealt.

Black colour on the Marimos mean a permanent damage on the Marimo Moss Balls.

The Solution to this will be to remove the black parts of the Marimos and save the left out green part reroll them and save it to a smaller ball.

After this is done you should find the direct cause which made an effect on your Marimos to turn black and decay and thereafter help the remaining part of the Moss to grow without any effect.

Main Reasons for Marimo Moss Ball Turning Brown or Grey.

Excess of Algae

Marimo Moss Balls with the Moss in it grabs other Algae grown in the tank toward it as much as possible. So leaving this Algae for a long time on the Moss will cause the Marimos to change in colour.

Insufficient Nutrient Absorption

When the Marimo Moss Balls don’t receive the proper amount of Nutrient they will change in colour.The Marimo Moss Balls like the other plant make food through the process of Photosynthesis. So if these Algae does not receive the enough amount of sunlight and unclean water will reduce their Nutrient Absorption.

Poor Aquarium Maintaianance

Poor Aquarium Maintainance is another factor which causes the Marimos to change in colour and Rot.

The Marimo Moss Ball or Container must be cleaned at least once a week or during the second week. If you take more time than that to clean the tank the water of the tank will get dirty and bring health problems on the Marimo Moss Balls.

Light Conditions

Marimo Moss Balls cannot survive themselves when there is too much light to it.Too much of direct Sunlight or too bright house light may damage the Marimos

Therefore they should be placed in the tank in a manner that they do not receive too much of light but at the same time they should be in the tank as all parts of this Algae receives the Minimum amount of light.

Inappropriate Substrate

Almost every tank has substrate added into it, when tanks are kept without cleaning for a long time, remaining of food particles given to fish, and other wastage in the tank go and hide among these Substrate. You might sometimes not notice this as the tank might be seen as clean while the debris lies within this Substrate. This might also cause problems on the health of the Marimo Moss Balls.

Can My Brown Marimo Balls Turn Green Again?

Following a few steps you can have the Marimo Moss Balls back in Green Colour.

Control Algae Growth

Controlling of Algae Growth is one way in which you can have the Marimo Moss Balls into their greeny colour again. Controlling of Algae Growth can be done reducing the unwanted amount of food that you feed to your fish and cleaning the Substrate in the tank so that hiding debris is removed.

Check the Lightning Levels

Keeping an eye on the Light received by the Moss Balls can also help them to change their colour from brown to Green Again. Always check that the Moss Balls receive the proper amount of light for its growth.

Add Proper Fertilization

Giving the proper fertilization to the Moss Balls will turn these Moss Balls from its Brown to Green Colour.

Check your Water Condition and Change Water

Clean water is always good for the health of the Marimo Moss Balls, checking the condition of the water and changing the tank water at least once a week or once in two weeks will help the Marimos from turning its Brown colour to the Green Velvety Colour.


Use a Filter and Clean your Tank

Using a Filter to your tank is a perfect advantage to your Tank. This will help absorb the debris collected in the tank and help the tank to be clean up to a certain level. This will be good for the Marimo Moss Balls.

Should I Remove Brown Marimo Moss Balls from My Aquarium?

Having Brown Marimo Moss Balls in your Aquarium might not be a suitable task.

Brown Marimo Moss Balls indicate that the Marimo Moss Balls are not under good health conditions. This is the cause of the tank water in which you hold your Marimos is not clean.

Sometimes this condition may worsen. Therefore Removing the Moss Balls from your Aquarium and holding it in another container until the Moss Balls recover might be suitable.

How can I tell if a Moss Ball is Healthy?

Green Moss Ball with a Velvety look in it shows that your Moss Ball is healthy.

The Water that these Moss Balls are clean and it receives the correct amount of light and Nutrition for its growth.

Is My Brown Marimo Moss Ball Dying?

A Change in colour of your Marimo Moss Ball to Brown means that the Marimo is sick but it does not mean that it is dying. This condition can be cured using some simple tasks. But if this condition is kept without attending to might worsen the Marimo Condition and change Black in colour and die.

Is Brown Marimo Moss Ball Bad for Fish?

Brown Marimo Moss Balls identified at the initial stage and treated might not have any Bad Effect on the Fish in your tank, but if these Brown Marimos are left untreated for a long time in your fish tank it will produce a toxic ammonia which will not be good on the fish and might even cause the Fish to Die.

Do Gold Fish Eat Brown Marimo Moss Ball?

As a herbivorous Gold Fish feed on plants and the Marimo Moss Balls too. They eat whatever they can put in their mouth. So the Gold Fish might even have a bite of these Brown Marimo Moss Balls.

Is Brown Marimo Moss Ball Harmful for Other Plants in My Aquarium?

Brown Marimo Moss Balls , like on the fish in the Aquarium might not affect the other plants in the Aquarium, until they are left unattended for a long time period and the toxic ammonia that they produce thereafter might affect certain other plants in the Aquarium.

Can I use Brown Marimo Moss Ball for My Aquarium?

You can have Brown Marimo Moss Balls in the Aquarium if the condition of these Moss Balls are not critically bad. And if you have given the relevant treatments on the Moss Balls which will help them in gaining their green colour back.

You can have the Moss Balls in the tank with an addition of a small amount of Salt.

But if the condition on these Moss Balls are bad looking, better place them in another container until they change in colour and add them back to the tank.

Proper Maintainance of your tank or container with Marimo Moss Balls is required so as to have Healthy Marimo Moss Balls and a Beautiful and Decorative Tank.

By Uswatta Liyanage

Hello. I'm Uswatta Liyanage from Galle, Sri Lanka. I am the founder of this website. Since my childhood I'm an aqua plant lover and I have professionally learned more about aqua plants. So I created this site for share my knowledge and experience with all of you. Now you can refer my site and feel free to contact me if any inquiry.