Marimo Care

Here are some of the Frequently Asked Questions on Marimo Care. By knowing this in advance, it will avoid you from repeating the common mistakes made by other Marimo owners

1. How do I rear my Marimo?

Marimos require water and very minimal light source to survive. It does not require feeding as it performs photosynthesis just like a plant.

2. What type of light source do I use?

Any source of natural or artificial light is good enough for your Marimo to live in a healthy and green condition. Never expose Marimo to direct sunlight as they grow better in cold and clean water.

3. Do I need to change the water? What water do I use?

Tap water is good enough. It is recommended to change the water your Marimo lives in once a week or every two weeks.

4. What should I do when changing water?

You may gently squeeze your Marimo to flush out any dirt trapped in it. You may also gently rolls your Marimo back and forth on your palm to help it retain its round shape. Marimos are living things and they need your love.


marimo care


5. Can I rear fish or shrimp alongside my Marimo?

Yes, definitely. However, for some goldfish, it might eat Marimo. So make sure you feed your fish well, or else Marimo becomes a buffet for them.

6. How long can my Marimo live?

The world’s largest Marimo is about 95cm in diameter. Marimos are able to grow about 5mm per year. Thus, the World Largest Marimo today is over 200 years old!

7. Why is my Marimo changing color?

Change in color from green to brownish shows that your Marimo is sick! Please wash your Marimo under running water and add some salt (5% of your water volume) into your Marimo container or tank.

8. How long can Marimo last without water?

In ideal conditions, Marimos can live for one month without water.

9. Why do Marimos float and sink?

More often, Marimos will sink in water. However, when Marimos perform photosynthesis, the oxygen bubbles generated by Marimo can make Marimo float up to the surface of the water. Don’t be alarmed as that is normal Marimo behaviour. Marimo can also float by squeezing them gently inside water.

10. Will Marimo reproduce? Is that possible to split it in two?

Yes, Marimo will reproduce when it is kept in a large pool of water. However, it is not recommend splitting up your Marimo. Very often you may damage it and it can cause it to die :(  If you are lucky your Marimo would reproduce and you would see a bump growing on your Marimo. Congratulations for that is your baby Marimo!

11. How can I help my Marimo grow faster?

You can help by lowering the temperature and improving the water quality. There are many other growth boosting products to boost Marimo growth! More info can be obtained here

12. Would high temperature affect Marimo?

Yes, direct sunlight would hurt your Marimo! If you wish, you can leave your Marimo with water in your fridge (fridge spa) for 24 hours to give it a nice cool environment to grow.

marimo care

13. Can Marimo survive in a fully sealed/covered bottle?

Yes, Marimos can survive in fully sealed/covered bottles. In fact closed bottles can keep out the dust and other pests that may harm your pet Marimo!

14. Will Marimo grow unevenly?

When growing, tiny pieces will grow unevenly around the Marimo. Marimo grows into ball shape due to constant water flow in the wild. As there is no water flow in your container, so please gently rub your Marimo to maintain its ball shape if this happen.

15. How to fix a split Marimo?

If the middle of marimo looks like want to crack, it means the filament structure of the marimo has been damaged. You can keep the marimo under the cold temperature all time to allow it the restructure its filament as soon as possible.

16. Why does the water turn brown so quickly?

It means the Marimo needs to bathe. Squeeze them under running water, and massage in between your palms gently to wash off the dirt.

Hope these guides answer most of your queries on Marimo.