Most marimo moss balls sold online are 1 to 4 cm. Our King is 10 cm, and it is a real, living marimo (Aegagropila linnaei), photographed in our own tanks.
Is it solid, or does it have a plastic core?
It is completely solid. There is no plastic core inside. That is the biggest difference between a real large marimo and a plastic core ball. A solid ball of this size is heavy, dense, and alive all the way through.
Why it does not float
Customers often see photos of small marimo floating and ask if the King floats too. Generally, it does not. A solid 10 cm ball is simply too heavy. It sits on the bottom of the tank, and that is normal and healthy for a ball this size.
The part most sellers do not tell you: the adaptation period
A ball this large needs a 6 to 12 month adaptation period after it arrives at your home. During that time, it needs real care. It is not a drop it in the tank and forget it plant. A solid living ball has to adjust to your water, your light, and your temperature, and large balls adjust slowly. If you want a no care decoration, this is not it. If you are a collector who enjoys caring for a living piece, this is exactly it.
Keep it cool. Heat is the enemy.
Large marimo cannot take high temperatures. Look at the setup in our photos and video: an LED light, filtration, and cool, clean water. That setup is not decoration, it is how these balls stay healthy.
Be especially careful in a hot summer. If a large ball yellows from heat, it is very hard to treat and bring back. Prevention is everything: cool water, gentle indirect light, and a water change every 1 to 2 weeks. Gently roll the ball during water changes so it keeps an even, round shape.
Shrimp love it. Shrimp are not required.
Shrimp graze on the surface of a large marimo all day, as you can see in our photos. They are great tank mates, but they are not a requirement. The ball does not need shrimp to stay healthy.
Why the 10 cm size takes about 2 months
Collector sizes are prepared to order. The 10 cm size may require approximately 2 months before shipment, depending on ready stock. Every order includes care instructions and our four week live guarantee: if your marimo develops a health problem during the first four week acclimation period, contact us with your order number and clear photos for a free replacement.
Our buyback policy for collector grade balls
Life changes. If you own a collector grade marimo of 5 to 10 cm and, for any reason, you cannot keep it anymore, you can sell it back to us. Moss Artistry buys back these balls so they go to a home that can care for them.
Two honest disclaimers. This is not an investment product, and we do not buy back at the original purchase price. It is a rehoming policy for living plants, nothing more.
One last note. These are cultivated marimo. Protected wild marimo are not harvested or sold.
Product link: Collector-Grade Live Marimo Moss Balls 2.2-10 cm, 10 cm size, $999. https://www.mossartistry.com/products/must-have-large-4-5cm-marimo-moss-ball-round-and-grow-slow
FAQ for the post: Q: Is the 10 cm marimo solid, or does it have a plastic core? A: It is completely solid living marimo, with no plastic core. That is the main difference between a real large ball and a plastic core ball.
Q: Does a 10 cm marimo float?
Generally no. It is heavy and sits on the bottom of the tank. That is normal for a solid ball this size.
Q: How much care does it need after it arrives?
Plan on a 6 to 12 month adaptation period with active care: cool clean water, indirect light, and regular water changes. Heat is the biggest risk. A large ball that yellows in a hot summer is very hard to save.
Q: Do I need shrimp?
No. Shrimp love grazing on it, but they are optional.
Q: Can I sell my collector grade ball back to Moss Artistry?
Yes, for collector grade balls of 5 to 10 cm that you can no longer keep. It is a rehoming buyback, not an investment product, and not at the original price.