A Complete Guide On Caring For Marimo Moss Balls

Last Updated on 2024-07-02

In stores, aquarium plants are often shown with a Marimo Moss Ball. However, a Marimo Moss Ball is not a true plant. It is a green algae that mimics moss. When filled with water, a Marimo Moss Ball becomes a squishy conversational centerpiece for any aquarium. To use Moss Balls, simply place them in the aquarium, where they can either float freely or settle to the bottom.

The good news is that growing a Marimo Moss Ball is a simple process. They can be housed singly, in pairs, or in groups of three or more, provided there is enough room. It takes a long time for them to mature, but they will visibly grow in size if their environment is favorable. To prevent it from becoming flatter on one side, especially if the water current is weak, it may be necessary to occasionally shift its position.

The maintenance and care for marimo balls are surprisingly simple for such a vibrant small plant. If you want to find out more, read on!

What Is A Moss Ball?

Marimo may look unnatural due to its amazing shape and appearance, yet these moss balls are made naturally, without any help from people. When it comes to algae, marimo moss balls are truly one of a kind. Growing conditions are ideal only in a handful of lakes in Japan, Iceland, Ireland, Scotland, and Estonia. Algae in these lakes have a velvety, fuzzy appearance and feel due to the movement of the waves as they grow into spheres.

There is no kernel or stone at the core of the sphere; rather, the interior is made entirely of solid algae that grow outward from the center at a snail’s pace of only 5 millimeters each year. They produce their own food through a process called photosynthesis and require very little effort on your part to care for them. Best of all, moss balls will not turn your tank’s water green like other forms of harmful algae. There are numerous benefits to having marimo as a tank mate, especially since they don’t create any waste.

Is A Moss Ball Alive?

Aquatic plants with the appearance of Marimo moss balls are rare. As a result of their flawless sphericity, they give the impression of being hand-made ornaments. However, they are real and full of life. Despite being a rare species of algae that develop naturally in a spherical shape in just a few distant locations worldwide, people have called them “Moss Balls” because of their resemblance to moss.

The moss balls have a three-stage life cycle.

  • Initial development occurs in the form of single-celled algae. They are at their most delicate and defenseless in this phase.
  • The second phase occurs when a group of cells is organized into a colony. At this point in their development, they begin to take on the round shape that is now characteristic of mature spheres.
  • In the third and final stage, they reproduce through budding. This method of reproduction does not involve a male and a female.

When the moss ball has grown sufficiently, it will have a small bump on its surface, which is the site where more moss balls will begin to form. Once this little moss ball cracks open, the “dormant chloroplasts” inside will begin to function. Then, this brand-new ball can exist on its own!

The average annual growth rate of a moss ball is just approximately 5 mm. But they have a long life expectancy! Japanese researchers discovered a moss ball that was more than a century old.

Moss balls in aquarius isolated on white background

Differences Between Java Moss Ball Vs. Marimo Moss Ball

Moss balls, whether they are Java moss balls or Marimo moss balls, make great additions to any aquarium. They are both very low-maintenance plants and can thrive in a variety of water conditions. However, there are some differences between the two types of moss balls that you should be aware of before you make a purchase. In this blog post, we will discuss the differences between Java moss balls and Marimo moss balls.

Java Moss

  • Java moss balls are made of taxiphyllum barbieri, which is a type of moss that originates from Southeast Asia.
  • Java moss balls can grow to be quite large.
  • Java moss balls are also more dense than Marimo moss balls. This means that they will sink to the bottom of your tank more quickly.
  • Java moss balls are easier to care for than Marimo moss balls. They can tolerate a wider range of water conditions and do not need to be trimmed as often.

Marimo Moss Balls

  • Marimo moss balls are made of Cladophora Aegagrophila, which is a type of algae that originates from Europe.
  • Marimo moss balls stay relatively small. This is because Marimo moss balls have a slower growth rate than Java moss balls.
  • Marimo moss balls are more buoyant and will float to the top of your tank.
  • Marimo moss balls require more upkeep and may not be ideal for beginner aquarium owners.

Real Vs. Fake Marimo Moss Ball

It depends on the store where you purchase your moss ball as to how easy or difficult it will be to select a healthy marimo. Keep an eye out for telltale signs to ensure you’re getting a genuine and healthy Marimo. There are many places to buy artificial moss balls because they look so much like the real thing.

So, be careful to pick the right ball. If you’re staring at these moss balls in the tank and aren’t sure which one is real, we’ve put together some guidelines to help you make the right decision.

  • Your first step should be to request help from the store owner. Roll the ball between your hands to get a feel for its shape. It should be easy to shape and mold into any shape you want. If it doesn’t change shape, it’s probably not real.
  • At the same time, it should feel fragile and stringy. A better way to say it would be fragile and firm.
  • It should feel smooth as you run your fingers over the moss and get a feel for its texture. It ought to have a crater-like, bumpy texture. The surface of a real marimo ball is full of craters, strength, hard parts, soft parts, and bumps. It’s probably fake if it’s too smooth or too perfect.
  • Most fake moss balls are made with a plastic ball, like a ping pong ball, in the middle and fake moss on the outside. You might be able to see this if you look through the moss near the center. If it has weird colors on the inside, it’s probably a fake.
  • Most of the time, a genuine Marimo will float in the water for a short while after being introduced to its new home in the aquarium before settling to the bottom. It needs to have the water squeezed out of it before it can float again.

How To Take Care Of Moss Ball

For those who have never cared for a plant before, a Marimo moss ball is a great option because of how simple it is to maintain. But here are some methods to make sure your moss balls grow and thrive.


The marimo do not need special or intense lighting because they form naturally at the lake’s bottom. Marimo usually doesn’t need any special lighting to photosynthesize under standard lighting conditions or with indirect sunlight from windows. They are usually able to thrive under the majority of aquarium bulbs. Brown stains on your Marimo may be a result of overexposure to strong light sources like direct sunshine or powerful LED bulbs. You may need to turn or rotate the ball of your Marimo if it will be sitting still for long periods of time.

Water Changes

By regularly changing the water in the tank, you can keep your Marimo clean and free of waste. Your Marimo’s water change % and frequency will be unique to the size and type of aquarium or container you use to keep them. The Marimo should have at least a 50% water change every two weeks if it is being kept in isolation from any other living things. If you keep the Marimo in a tank with animals and other plants, you may need to change the water more often.

Cleaning Marimo

You may need to clean your moss balls sometimes if you don’t keep your Marimo with algae-eating critters (such as dwarf shrimp and some types of fish). To do this, remove your Marimo from the water, give it a quick rinse, drain the water, and place the ball in a clean container of water.

At the same time, it’s a good idea to roll the ball gently back and forth between your hands. Without the constant rocking and rolling of a lake, your Marimo may end up with an unnatural deformation. The ball can be rolled gently to restore its roundness.

Tank Companions

Marimo may share an aquarium with a wide variety of other fish. However, Goldfish, specific species of Plecostomus (Plecos), and large crayfish can eat or damage Marimo balls.

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What Temperature Is Best For Marimo Moss Ball?

Marimo moss balls in the wild inhabit waters that are cool and dark, and the waves progressively turn them so that they are exposed on all sides to the light. When kept inside, they should be maintained in sterile, frigid water with dim lighting. Every two weeks or so, give them a good rinsing and change the water in their container to get rid of any leftover sediment. Utilizing the water from the faucet is quite acceptable.

The temperature shouldn’t rise above 77 degrees Fahrenheit (25 degrees Celsius). You can place the moss balls in an area that receives low levels of natural or artificial light. Keep them out of the direct sunshine because it will cause them to burn and could even be fatal.

What Are The Light Requirements For Marimo Moss Ball?

The lake bed is home to the Marimo moss ball. That means it receives indirect lighting rather than full sun. They spend their nights at the lake’s depths, but they come to the surface during the day to absorb sunlight and expel oxygen into the atmosphere.

If possible, an east-facing window is ideal. When growing in a glass container, the same concept applies since the glass can direct light, producing a greenhouse effect, and heating the water. Warm water is bad for your marimo moss ball plant, so keep the water temperature cooler. The truth is that soaking marimo balls in warm water might cause them to discolor. It is recommended to position the container at least a meter away from any south or west-facing windows.

Marimo Moss Ball Growth Rate

The slow growth of only 0.5 centimeters per year makes these plants ideal for small aquariums because you won’t need to prune them, and they won’t overwhelm your space. Even though it could be years before your ball gets that big, the benefit of a slow growth rate is that you can always divide it into smaller pieces once it gets there. In addition, these can live for over a century, so count on having one for the rest of your life.

Marimo moss balls in the wild can grow to be 8 to 12 inches (20 to 31 cm) in diameter, but your homegrown Marimo moss ball probably won’t get quite this big. Fertilizers and carbon dioxide (CO2) injection are methods suggested by some for speeding up growth.

Marimo Moss Ball Parasites

The use of moss balls as decorative accents in aquatic and terrestrial environments has gained popularity in recent years. These moss balls are a great way to bring some greenery into your home with minimal effort. Yet, there are some concerns about these moss balls. The question of whether or not moss balls contain worms is a common one.

The short answer is that moss balls can have worms. These worms, however, are not the same as the ones you might find in your backyard garden. Moss-ball worms resemble detritus worms. Don’t freak out if you discover a worm in your moss ball. The worm can be easily removed, and the moss ball can be given a quick rinse in the sink before being placed back in the tank. Your moss ball will turn out just fine, don’t worry!

Do You Feed A Moss Ball?

Marimo balls that have been domesticated are low-maintenance pets that are great for new owners. They’re great for simple, low-tech aquariums because they’re compatible with all fish types. These moss balls, like other types of moss, produce their own food through photosynthesis and thus need neither outside nutrients nor any special care to thrive.

All the vital nutrients required can be obtained from exposure to light and water alone. Organic matter from nearby fish is another source of nutrition for these creatures. This is great for the health of your tank because the moss balls will thrive on the nutrients it provides. They are completely self-sufficient because of this method of obtaining energy. There is no need to use CO2 or fertilizer to grow moss balls, but doing so will hasten the process if you’d like.

Marimo Moss Ball Ph Requirements

Marimo moss balls are a type of algae that live in freshwater environments. They are often used as decoration in fish tanks and require specific conditions to thrive. Marimo moss balls are low-maintenance and can thrive in a wide range of water conditions. However, they do have some specific requirements when it comes to pH levels. Ideally, marimo moss balls should be kept in water with a pH level between 6.5 and 7.5

Marimo moss balls prefer slightly acidic water. If the water is too alkaline, the moss balls will not be able to absorb nutrients and will eventually die. Fortunately, it is relatively easy to adjust the pH of your aquarium water using chemicals such as sodium hydroxide or hydrochloric acid. With proper care, your marimo moss balls should thrive for many years to come.

Marimo Moss Ball Reproduction/Marimo Moss Ball Propagation

There is no longer any need to physically visit a store if you are in need of additional Marimo Moss Balls for your aquarium. If you use a straightforward technique called vegetative propagation, you can get more from your existing moss balls. It’s when you cut off a piece of a plant and nurture it so it matures without using any seeds. Even though it doesn’t produce seeds, Marimo moss can be easily propagated thanks to its algal status.

Just follow these steps, and you’ll have many moss balls in no time!

Step 1:  First, locate the balls you want to reproduce. Make sure it’s large enough to be divided into at least three pieces. However, before doing that, you should give it a good squeeze to remove excess water and let it air out for a while. They’re fragile, so be careful if you want to squeeze them.

Step 2:  Now, take a razor or sharp knife and divide the ball into halves or thirds. If the resulting pieces look like they’re more than 2–3 inches in size, cut them in half again to make sure. Now. You can multiply your Marimo ball population by a factor of 4-6!

Step 3: You can’t just drop the pieces you just cut into the water and leave them there. They will develop unevenly if you don’t first reinforce their shape. To do so, take a piece of string and wrap it around the moss in a cross pattern, giving it a roughly spherical shape; then, just like when you’re wrapping a present, secure the string in place with a knot.

Step 4: Next, fill the tank with fresh aquarium water, or use glass or high-quality plastic jars to hold the pieces until you can add them to the tank. It needs to be exposed to sufficient light for photosynthesis to occur. In addition, the water shouldn’t be any hotter than 78 degrees Fahrenheit.

Step 5: Once it’s been placed in the tank or jar, you should turn it every few days. Because without light from all directions, it can’t develop into a perfect sphere. Keeping it rotated at regular intervals will help it develop into a round ball.

What Are The Benefits Of Marimo Moss Ball?

In order to provide the best possible environment for aquatic animals, live plants should be included in every aquarium. It can be a hassle to care for these plants because they typically don’t live very long and require constant attention. Yet, if you’re set on marimo moss balls, you won’t have to worry about any of these things. This moss is not only low maintenance, but it also has many other applications in a fish tank.

Take up Nitrates

Nitrates, nitrites, ammonia, and phosphates build up in your aquarium when fish waste is not removed. Like any other form of life in your aquarium, moss balls filter the water and remove harmful substances.

Oxygenates Tank Water

Moss balls, like all plants, use photosynthesis to produce food. This means they can take in carbon dioxide and give off oxygen. As the excess oxygen in the tank dissolves into the water, you may be able to see your marimo floating in the tank. The well-being of your fish and other aquarium inhabitants depends on keeping the aquarium’s water oxygenated at all times.

Limits the Spread of Algae

Fighting fire with fire best describes using algae to prevent algae, right?

Having marimo in your tank is a great way to cut down on unsightly algae because it consumes the nutrients that the other kinds of algae need to grow.

Maintain Helpful Bacteria

Having a healthy tank requires striking a balance between the bio-load and the filtering systems. Colonies of beneficial bacteria flourishing in our tanks are one of our most potent weapons in the war against water pollution. Moss balls provide a surface to grow on and beneficial seeding material.

Minimal Upkeep

You already have everything you need to maintain a thriving moss ball if you keep fish in a tank. They thrive on the waste produced by your fish and require very little light. Although they thrive best in the shade, they can survive in a wide range of conditions.

High-pH Adaptation

Most aquarium plants cannot tolerate water with a pH above 8, but a moss ball will thrive in this range.

No Dead Matters with Moss Balls

As part of their life cycle, most plants constantly replace old leaves with brand-new ones. Certainly not Marimo.  Both their growth and reproduction rates are slow.

No Anchoring Needed

You won’t need to worry about having a specific substrate in your tank or doing any extra work to anchor them like you would with other aquatic plants. While it’s not required for a marimo to be healthy and happy in an aquarium, they’re adaptable enough to let you do so if you’d like.

A Really Tough Addition

If you don’t intend to kill a marimo, you have “almost” zero chance of succeeding. A moss ball will perish in unfiltered tap water, salt water, or nutrient-free water, but short of that, it will persevere.

Moss Ball’s Aesthetic Value

We have spent a lot of time discussing the benefits of a moss ball for your aquarium. There is one thing we haven’t mentioned yet that should be obvious but isn’t. They are simply attractive. You and your fish will have a better time in your aquarium if you add one or more of these colorful decorations.

How To Clean A Moss Ball

Green algae, such as the moss balls found in aquariums, provide shelter, climbing surfaces, food sources, and a comfortable place to relax for the aquatic animals that live there. They look fantastic as tank decorations, even if you don’t have any fish or other aquatic animals. It’s important to keep your aquatic moss ball clean for whatever purpose you have for it, as debris like food, rocks, and invasive algae can cause it to become dingy, dark, and unappealing if left unchecked.

Here are the steps to properly clean your moss balls

  1. To clean your moss ball, grab a bucket of aquarium water. Fill a bucket with aquarium-safe, purified, dechlorinated water. Ensure a pH of 6.0 to 8.0 and a temperature of 72 to 78 degrees Fahrenheit (22 to 26 degrees Celsius).
  1. Squish moss ball into the aquarium water. Put the moss ball in the aquarium water in the bucket. Now, begin squeezing it softly to expel the grime it has accumulated. If you don’t want the ball to absorb dirty water from the bowl after your final squeeze, take it out of the bowl before letting go.
  1. Use your palms to roll the moss ball into a sphere. It’s possible that your moss ball will lose its form after you clean it. Indeed, it’s possible for it to shatter under certain conditions. It can be restored to its spherical form by giving it a light roll between your palms.
  1. Reintroduce the moss ball to the fish tank. Moss balls, once returned to the aquarium, should rise to the top. When this happens, it means there is no longer any moisture trapped inside. Just let it sit in the water for a while, and it will eventually sink to the bottom of your aquarium.

What Fertilizer To Use For Marimo Moss Ball

As a form of algae, Marimo Moss Ball is frequently used as an ornamental plant in aquatic ecosystems. It takes little effort to maintain and doesn’t need a lot of fertilizer. Photosynthesis is how the Marimo moss ball creates its food. But since the average annual growth rate for a Marimo is only 0.05 mm, aquariums and tank owners are increasingly resorting to the use of special nutritions in an effort to speed up its growth.

Here are some of those growth-inducing fertilizers.

Luffy Plump Marimo Fertilizer

Luffy Plump  Marimo Fertilizer is a nutritious liquid diet developed just for the Marimos. Its high calcium content promotes robust, green growth in Marimos, while its phosphate and nitrate content facilitates proper nutrient uptake.

Marimo Moss Ball Liquid Plant Fertilizer 80z

Food for Marimo is the Liquid plant Fertilizer 80z. The Nitrates, Phosphates, and Salts in this fertilizer are specifically formulated for a Marimo. Note that this fertilizer is strictly a food and does not contain any Marimo.


To ensure rapid and substantial growth, CO2 must be supplied to your Marimo.

Infusing CO2 into your Marimo can be done in two different ways.

  • Just get some CO2 solution, put the Marimo Balls in a container, and shake!
  • To provide the plant with the necessary CO2, simply place the Marimos in a container of Seltzer water for a few hours.

Overfertilizing can cause the algae to become brittle and fall apart, so be careful. Your Marimo Moss Ball will flourish and bring you joy for years to come with just a little TLC.

How To Tell If Moss Ball Is Healthy

Marimo moss balls are a popular type of aquarium plant, known for their fuzzy green appearance and ease of care. While they are tolerant of a wide range of water conditions, there are a few signs that indicate a healthy marimo.

  1. A healthy marimo moss ball will be firm and spherical in shape. If your marimo is starting to flatten out or develop wrinkles, it may be a sign that it is not getting enough light.
  1.  Another sign of a healthy marimo moss ball is its color. The algae should be a vibrant green, with no brown or yellow patches.
  1. A well-cared-for plant will slowly grow over time. If your plant is shrinking, it may be an indication that it is not getting enough light or nutrients.
  1. You should see new growth on a healthy marimo moss ball. If your marimo isn’t showing any of these signs, don’t worry! Just give it a little TLC, and it should be back in good health in no time.


Can You Put A Moss Ball With A Betta Fish?

It’s perfectly alright for betta fish and moss balls to coexist. Betta fish enjoy marimo moss balls for more than just their lush, velvety green beauty and striking contrast to the other ornaments in the tank.

Can You Squeeze A Moss Ball?

Simply giving a moss ball a light squeeze will do the trick when it comes to keeping it clean. Furthermore, don’t be afraid to try squeezing a moss ball to assess the plant’s vitality; it’s a simple and quick method.

Can I Put Marimo Moss Ball And Goldfish Together?

Marimo can share an aquarium with a wide variety of fish and other tankmates. However, Goldfish, particular species of Plecostomus (Plecos), and large-sized crayfish may eat or damage the Marimo balls.

Can I Put Marimo Moss Ball With Shrimp?

Shrimp are among the best tank mates to have when keeping Marimo moss balls. Marimo moss balls make a great decoration for a shrimp tank because they absorb nitrates, release oxygen, prevent algae growth, and require less care than most other aquatic plants.

Can I Put Marimo Moss Ball With Fish?

Marimo moss balls do well in large aquariums as well as smaller containers like fish bowls, jars, and vases. They can live alone or with fish and other invertebrates.

Can I Put Moss Ball And Snails In A Tank?

Marimo balls are just as beneficial as live plants, mosses, and other algae in a tank with freshwater shrimp and snails. They collect small bits of food and debris, making for a great grazing area for invertebrates, and they provide a lot of surface area for biofilm to form.

Do Fish Eat Marimo Moss Ball?

Marimo moss balls can share an aquarium with a wide variety of fish and other tankmates. Some fish and invertebrates, such as Goldfish, certain Plecostomus (Plecos), and large crayfish, may eat or damage Marimo balls.

How To Tell If Your Moss Ball Has Zebra Mussels?

Checking your moss balls for invasive zebra mussels can be done visually and by feeling for hard shells. You must keep in mind that they may be quite diminutive.


If you’ve made it this far, we hope you found it interesting. These intriguing moss balls are in most aquatics stores. Aquarists treasure them for their unusual shape and often keep them in jars or old fishbowls. If given the proper attention and care, marimo balls can live for many years, during which time they can either grow to be quite large or split into several smaller marimos. Don’t get your hopes up, though; the average marimo’s growth rate is just 5 mm per year!

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