Are Moss Balls Good For Turtle Tanks?

The moss ball is a popular addition to many fish tanks. Many hobbyists are fascinated with the round, fluffy balls that roll around the bottom of fish aquariums everywhere. Today we discuss if they have any added value to a Turtle tank.

Can I Put A Moss Ball In My Turtle Tank?

Fish tanks make use of moss balls to clear their tank water and feed their fish.

With the amount of waste a Turtle makes, it’s a great idea to put a moss ball in its tank. That’s because moss balls reduce the smell of waste and help clarify tank water. They’re completely safe for Turtles, but some imported moss balls are proven to be dangerous for the environment. See the issue below.

Issue: Are Marimo Moss Balls Illegal In The US And Canada?

Before you go online or run to your local pet store to buy a moss ball, please note the following important information about Marimos.

There was an issue in March of 2021 with zebra mussels being found in Marimo moss balls imported from Ukraine. All Marimo moss balls from the source were ordered destroyed and tanks sanitized. After tracing and contaminating the products, federal guidelines for importers were set in September of 2021. I strongly recommend you researching government websites for updated information.

Here is the USGS link and Govt. of Canada link for your information.

Zebra mussels are a highly invasive species and could ruin not just your tank but our natural bodies of water if they’re let out in the wild. Turtles like Map and Terrapins can eat zebra mussels but not all. If you found the mollusks living in your tank, please destroy them by crushing them.

If you’ve already purchased these types of Marimos and have found zebra mussels, please get rid of them by freezing them overnight in a ziplock bag or boiling them before disposing them in a garbage can. This is so that all zebra mussel larvae (that’s too small for the naked eye to see) would be killed with it. Then you should sanitize your whole aquarium.

You can find more information about zebra mussels and moss balls here and here.

So there are no issues with the moss balls themselves but the problem lies in what they may be carrying. Make sure you have a safe and vetted source with recent reviews to avoid this problem.

Artificial moss balls don’t have this issue.

There are natural moss balls and artificial moss balls.

Marimo moss balls are the kind that’s naturally found in lakes in Japan, Iceland, and Ukraine. They’re not made of moss but are a type of rare algae colony (Aegagropila linnaei) that gets its shape from being rolled around the lake’s gentle waves.

The Japanese word “Marimo” literally means “bouncy ball of plant”. They’re revered in Japan and are considered pets. They can often be found in this country in nano tanks, jars, and aquariums along with fish or on their own.

In the Western world, Marimo moss balls became famous when aquarists began importing them for their use.

On the other hand, artificial moss balls, like the Exo Terra Clarity and Odor Control, are used as a deodorizer in a Turtle tank. It’s made of a soft synthetic material mimicking the Marimo but contains activated charcoal, providing chemical filtration in any tank.

It’s not live moss, nor is it algae, so don’t expect any growth, unlike the Marimo. Users claim that this product is effective in vastly reducing the smell in a Turtle tank. They also say that they had to change their filter media less because of the efficiency of the moss balls.

Do Moss Balls Help Tanks?

Other than its cute and fluffy appearance, moss balls do have important and helpful functions in an aquarium.

Moss balls provide benefits not just to Turtle tanks, but any kind of aquarium you have in keeping the water clear and removing odors. They also become a food source for Shrimp and algae-eating fish. The artificial moss balls remove bad odor and provide chemical filtration to your water.

Moss balls for turtle tank
Do Moss Balls Help Tanks?

Here are some advantages of having moss balls in a Turtle tank:

  • They get rid of the strong Turtle-y smell

Most users of moss balls swear by their efficacy in odor control. As a result, your tank will need less cleaning. Don’t completely depend on the moss balls, though, and stay with your scheduled water changes.

  • Marimo moss balls naturally consume nitrates and ammonia

Moss balls are, in fact, algae. They are great at keeping those nitrates down. Algae also help consume ammonia when it is present in the water.

  • Oxygenation and water clarity

Turtles may not need oxygen in the water but oxygenation creates water movement. This helps keep the water clean. Both Marimo and artificial moss balls help the water stay clear.

  • Most Turtles don’t bother moss balls

One of the best things we can do for our pet Turtles is make their surroundings look as natural as possible. Moss balls blend in perfectly in the environment.

Both kinds of moss balls are green and look like regular plants in the tank.

Because of their looks, Turtles may try to eat them as they’re fond of “tasting” anything new. But they’ll leave it alone when they lose interest. When Turtles do take a bite off of your moss ball, it’s okay as they won’t harm your pets.

If you don’t want your Marimo moss balls eaten by your Turtles, you can break them down into smaller bits and stuff them into holes in your decor using your fingers or a pair of tweezers. They would look just like plants and your Turtles will stop bothering them.

Don’t make them too small, though, as they may come loose and clog up your filter.

If you are interested in learning more about your fish behavior, check out the links below:

How Long Do Moss Balls Last In Turtle Tank?

Now that we know that moss balls are helpful, let’s find out how long they can stay that way.

Moss balls for turtle tank
How long do moss balls last in Turtle tank?

Unless torn or bitten by your Turtles, an Eco Terry Clarity and Odor Control will last for about 3 months at best, while Marimo balls are claimed to live up to 200 years or more. As a matter of fact, they are passed down as “pets” in Japan from the elderly to the younger generation.

You’ll know when artificial moss balls are done when your tank starts to emit the unmasked odor of your Turtle’s waste. This happens after a couple of months or more of use.

For Marimo moss balls, you know there’s something wrong when they start to turn brown. This means that they’re lacking in nutrition. But they will normally outlive you with proper care.

To prevent Marimo moss balls from turning brown, do the following:

  • Squeeze them gently to get rid of debris once or twice a month. Since they act as filters, they’ll accumulate dirt inside of them which you can easily remove with a slight squeeze.
  • Turn them upside down every once in a while so all parts get enough light. Marimo balls are algae and they need light to survive.
  • Don’t put them in high-temperature tanks. They grow naturally in colder waters so they’re not used to warm waters.

It’s also good to roll them in your hand every water change so they stay in shape.


The moss ball is a very good idea for a Turtle tank as it helps in many ways. The choice lies in whether you want to use the natural or the artificial variety. Both have their pros and cons, so assess what your Turtle needs and how you think it will react to each kind.

Recent Posts