What Do Moss Balls Eat? The Truth About Their Nutrition

Moss balls are fascinating, living algae spheres that don’t consume food like animals or plants with roots. But what do moss balls eat? Instead of feeding, they absorb everything they need directly from their surroundings.

If you’ve ever wondered how these fuzzy spheres survive, this guide covers their nutrients, natural habitat, growth process, and lifespan while debunking common myths. By the end, you’ll know exactly how to keep them thriving.

Do Moss Balls Eat? How They Get Nutrients

Moss balls don’t have mouths or roots. Instead, they absorb nutrients through light, water, and oxygen exchange. This simple process keeps them alive and growing. Let’s go deeper:

1. Light as an Energy Source

Moss balls rely on photosynthesis to create energy. Like plants, they take in sunlight or artificial light and convert it into food. 

• Indirect light is best, too much direct sunlight can cause them to turn brown.
• They can survive in low light, but their growth will be slower.

A balanced light source supports light and moss ball growth, helping them maintain their structure and continue thriving. Read more about how light affects moss balls.

2. Absorbing Nutrients from Water

Instead of drawing food from roots, moss balls absorb nutrients directly from their environment. These include:

• Nitrates – Byproducts of organic material that moss balls use for growth.
• Phosphates – Essential for their photosynthesis process.
• Minerals – Like iron and calcium, which contribute to their strength.

Because they absorb nutrients through their surface, fresh water is essential for a healthy moss ball diet. Without regular water changes, they might not get enough minerals to grow properly.

3. Oxygen Exchange

Moss balls also contribute to their surroundings by absorbing carbon dioxide and releasing oxygen. This exchange helps maintain a healthy water balance, just like aquatic plants do. 

What Do Moss Balls Eat in the Wild?

Photo credit: Tofugu

In their natural habitat, moss balls grow in cold, freshwater lakes and slow-moving rivers across regions like Japan, Iceland, and parts of Europe. They roll along the lake bed, absorbing nutrients from the water.

Their food sources in the wild include:

✔ Tiny organic particles that naturally float in the water
✔ Dissolved minerals like calcium and phosphorus
✔ Sunlight, which helps them photosynthesize

Since they roll with the current, they stay clean and free of debris, maintaining their signature round shape.

What Do Moss Balls Eat in a Jar?

Photo credit: Sravya

If you have a Moss Amigos moss ball at home, you might wonder if it needs extra feeding. The answer? No, it doesn’t. Everything it needs comes from its water.

To keep it healthy:

✔ Change the water every 2-3 weeks to refresh nutrients.
✔ Provide indirect light for photosynthesis.
✔ Rotate it occasionally to prevent dirt buildup. You can use a moss handler to keep it clean and maintain its shape.

Since moss balls don’t need fertilizers or special food, they’re one of the easiest living moss balls to care for. 

How Moss Balls Grow Over Time

Moss balls have one of the slowest growth rates among algae-based organisms. They grow about 5 millimeters per year, which means noticeable changes can take years or even decades.

Their growth rate depends on:

• Light exposure – More light means slightly faster growth.
• Nutrient availability – Fresh water supplies key minerals.
• Water movement – Rolling keeps their surface clean.

Because of this slow moss ball growth rate, they remain compact and don’t require trimming or special care. Learn more about how moss balls grow and how long they live.

Common Myths About Moss Ball Nutrition

1. "Moss balls need fertilizer."

No, they absorb nutrients from the water naturally. Adding fertilizer can actually lead to excess buildup. Too many nutrients can cause unwanted algae growth, which may harm the moss ball.

2. "They eat algae."

Moss balls are a type of algae but don’t consume other algae. Instead, they absorb nutrients from the water to sustain themselves. Learn more in Marimo Moss Balls vs. Algae.

3. "They need soil or a substrate."

Nope! Moss balls don’t have roots and live freely in water. They take in everything they need directly through their surface.

4. "They stop growing if they don’t get fed."

Their growth rate is naturally slow, but as long as they have light and fresh water, they continue developing. Some moss balls in the wild have been growing for over a century!

How to Support Moss Ball Growth

Even though moss balls don’t eat, you can still help them thrive by providing the right conditions.

🌱 Keep the water fresh – Changing it every couple of weeks maintains minerals.
☀️ Provide soft, indirect light – They need light for photosynthesis but not too much.
💨 Move them occasionally – Rolling them gently prevents dirt buildup and keeps them round.

With proper care, a moss ball can live for generations, making it one of the longest-living, low-maintenance algae spheres you can keep.

Final Thoughts: What Do Moss Balls Eat?

Moss balls don’t eat in the traditional sense. Instead, they absorb nutrients, minerals, and light from their surroundings. In the wild, they take in organic particles and dissolved minerals from freshwater lakes. At home, regular water changes and proper lighting are all they need to stay healthy.

If you’re looking for a unique, low-maintenance living organism, moss balls are an excellent choice. Now you know exactly how they survive and thrive!

If you want to learn more facts about their growth, care, and lifespan, check out Marimo Moss Ball Facts.

Frequently Asked Questions

Do moss balls need food?

No, moss balls don’t need food like fish or rooted plants. They absorb everything they need from water and light. As long as the water is clean and nutrient-rich, they stay healthy.

Can moss balls survive in tap water?

Yes, but it depends on the water quality. If your tap water contains chlorine or heavy metals, letting it sit for 24 hours or using a water conditioner helps. Clean, untreated water is best for moss ball health.

Do moss balls produce oxygen?

Yes, through photosynthesis, they release oxygen into the water. This can benefit aquatic environments by helping maintain oxygen levels. However, they are not a replacement for an air pump in fish tanks.

References:

Phillips, N., Draper, T. C., Mayne, R., & Adamatzky, A. (2019). Marimo machines: oscillators, biosensors and actuators. Journal of Biological Engineering, 13(1). https://doi.org/10.1186/s13036-019-0200-5

What is nitrate? | US EPA. (2025, March 10). US EPA. https://www.epa.gov/mn/what-nitrate

The Editors of Encyclopaedia Britannica. (2025, March 12). Phosphate | Fertilizer, Agriculture, soil. Encyclopedia Britannica. https://www.britannica.com/science/phosphate