Why Are Aquarium Plants Pearling?

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If you have noticed tiny pearl-like bubbles sprouting from your aquatic plants, you’re not the first and you’ll definitely not be the last. But what is the reason for the phenomenon and is water pearling healthy for your tank?

What makes aquatic plants pearl and why does the pearling effect specifically occur after a water change?

To understand the concept of plant pearling, you need to have a detailed understanding of photosynthesis. All plants produce oxygen through photosynthesis during the day.

The plant then releases the created oxygen through its tissues. Some plants release the gas in bubble form, visible on the leaves and stems.

In the case of aquarium plants, they produce oxygen at a higher rate, which is where the pearling effect comes from. Remember that regardless of whether your aquatic plant pearls or not, it is not an indicator of disease, decay or other problems.

Your plants are healthy so long as they show good growth. Plant pearling is just a pretty indicator of their healthy growth and stable physiology.

What Is Plant Pearling?

Pearling is a common occurrence in most aquatic plants. Plants, in general, produce oxygen during photosynthesis and release it through their tissues.

In a tank, the aquatic plants release the oxygen through their tissues, which takes the form of visible bubbles. The bubbles covering the plant’s leaves and the stem are nothing more than trapped oxygen.

Aquarium plants release oxygen much faster than regular ones, causing them to release hundreds of bubbles every day.

This process is known as pearling because these bubbles resemble that of the shiny pearls. It is undoubtedly one of the prettiest sights in an aquarium.

Why Do Aquarium Plants Pearl?

While pearling is not a must for all aquatic plants, it is common in plants that receive more light or CO2 regularly. Similarly, you may not witness much pearling if there is not a lot of current in your tank.

While the pearling effect in your tank can make for a delightful effect, you should not force it by raising the amount of light in your tank.

The pearls occur due to the oxygen emitted by the plants during photosynthesis. Pearling is never an indication of plant health.

It only means that your aquatic plants are saturating the water with oxygen.

Is Pearling Good or Bad for Aquarium Plants?

All pearling plants are healthy. On the other hand, not all healthy plants produce bubbles or the pearling effect.

Your plants may or may not create pearls based on the saturation of gasses, availability of light, and several other factors.

A pearling plant does not mean it is healthy or unhealthy. It only indicates that your plant is releasing oxygen through photosynthesis.

If you are worried about your aquatic plant’s health and integrity, you need to look for other signs of disease or rot. The little pearls are not harmful to the fish or other invertebrates in your tank, quite the contrary.

The pearling effect is a great indicator of a healthy and stable environment, especially for aquatic creatures that thrive in oxygen-rich habitats.

How To Make Aquarium Plants Pearl?

Photosynthesis occurs with 6 CO2 + 12 H2O + photons (light energy). All plants produce 6 numbers of O2 (oxygen), 6 numbers of H2O (water), and glucose during photosynthesis.

If you wish to make your aquarium plants pearl, a good way of achieving that includes ramping up the CO2 content or boosting the light intensity in your tank.

There are a few other methods linked to the bubbling effect, so let’s dissect them:

Water Change

Most aquarists vouch that they see the prettiest pearling effect right after performing a water change.

The science behind it is that tap water has a high gas content, which helps speed up the photosynthesis process and stimulates plant pearling.

Alternatively, you may fill your tank with reverse osmosis (RO) water. The ideal way to achieve this would be to keep RO water in reservoirs and place a circulation pump in your tank.

Moving water tends to hold more gas than standing water, leading to more water bubbles.

Increase CO2

Anybody with a decent knowledge of chemical processes would know that carbon dioxide is more soluble in water than oxygen.

If you were to inject CO2 into your aquarium, the gas will saturate the water quickly. The CO2-pressurized water will speed up the rate of photosynthesis in your aquatic plants and produce more oxygen, resulting in more bubbles.

While pressurized CO2 is one of the best ways to encourage pearling in aquarium plants, too much carbon dioxide in your tank can promote algae growth.

You must exercise caution while adding high levels of CO2 to the tank. This can lead to some logistical problems, as you’re trying to improve plant and fish health and contain algae spread at the same time.

Fortunately for you, I’ve already written extensive articles regarding algae control, so you might want to check those out.

Algae aren’t necessarily bad for the environment, especially since many fish and other aquatic creatures take them for food sources.

But algae overgrowth will impact the environment negatively.

Increase Light Level

Some of the most reputed aquarium lighting brands come with a feature that allows aquarists to adjust the light intensity.

Increasing the light intensity in your tank can increase the rate at which photosynthesis occurs, producing more oxygen bubbles or pearls.

However, you must increase the light intensity gradually, or it can be difficult for your plants to adapt.

The downside of this method is that high-intensity aquarium lights can promote the growth of Black Beard algae, which are notoriously difficult to remove from your tank.

To counter this effect, provide your plants with a healthy lighting cycle and keep the light intensity moderate. Plus, you should always have a set of prevention methods in place to counter Black Beard algae.

Adding some algae eaters to the environment is a good way of countering this type of algae naturally, but this only works when the algae are young. Few species can consume fully matured Black Beard algae due to their harder tissues.

Regular tank maintenance is another necessary procedure since it allows you to clean algae deposits and keep the environment fresh and stable.

Ultimately, Black Beard algae aren’t toxic and won’t change the water’s chemistry. But they will restrict the plants’ access to light by covering them almost completely in some cases.

So, manage the lighting carefully, since Black Beard algae can suffocate the environment quite fast when unattended.

Add More Plants

One of the top hacks to creating the pearling effect is to create a densely-planted tank. This can increase your chances of witnessing the pearling all day long. Plants like Rotala H’ra, Mayaca Fluviatilis, Pearl weed, etc., produce the best pearling effect in a home aquarium, beautifying the environment like few others can.

Adding lots of plants to your tank transforms your aquarium into an oxygen-producing machine, saturating the water with oxygen much faster and causing plenty of pearling.

This point has 2 potential problems worth discussing. One is the competition over available nutrients.

Aquarium plants live in a closed environment, so they will naturally compete over the same nutrients. If the available nutrients are insufficient, the plants will starve and die.

The second problem is having too many plants in fish tanks. While fish need plants for a natural-looking setup, reliable oxygen production, and hiding areas, they also need some open space for swimming.

Keeping fish in a plant-crowded environment will stress them out and even affect their health to a certain extent.

Then you have labyrinth breathers like bettas that need to reach the water surface occasionally to take some gulps of air. If the plants prevent them from doing so, they might suffocate.

Having too many plants will also make it more difficult to clean the tank properly. So, you need to consider these aspects before overburdening your tank with plants.

Personally, I would only recommend this plant-rich approach in plant-only tanks, but don’t let my opinion stop you.

Trim Your Plants

Trimming or propagating your stem plants encourages the growth of new shoots and leaves. Trimmed plants often tend to create more pearls after they get cut.

The newly cut stem or leaves often releases more gas, which causes the plants to engage in photosynthesis and produce a stream of bubbles flowing from the severed area of the plant.

Increase Water Temperature

If your fish can tolerate a slight rise in the water temperature, you may try it to stimulate your plants to pearl up.

Many aquarists vouch that aquatic plants produce more pearls in warmer waters.

Turning off the filter and powerheads may also create the most spectacular pearling around your plants. Powerhead pumps and other devices often cause a current inside your aquarium, blowing away any bubbles or pearls that the plants might produce.

Just turn off the powerhead for an hour or two and your plants should boost their pearling power extensively.

Five Best Pearling Aquarium Plants

Pearling aquarium plants are nothing more than your usual tropical plants capable of hyper-photosynthesis when fully submerged in a freshwater aquarium.

Here is a list of the best oxygen-producing aquatic plants to consider:

1. Elodea

Elodea also goes by the name waterweeds and are excellent plants for aquariums. Schools and educational institutions use the elodea plant to teach and demonstrate cellular structures, chloroplasts, nuclei, and how plants produce oxygen during photosynthesis.

This is one of the highly sought-after aquarium plants for its fast growth and high oxygen production.

Its ability to boost oxygen levels is responsible for the most spectacular formation of pearl in fish tanks.

2. Bacopa

Bacopa Monnieri, also known as Moneywort, is a well-known aquatic plant that is easy to care for, versatile, and thrives in low-tech setups and aquariums.

They are prolific and easy to prune, making them one of the best midgrounds to background plants.

These plants are perfect for beginners and work great for filling space and adding dimension to any aquascape. Bacopa grows fast whether immersed or submerged.

This popular aquarium plant is a popular choice among aquarium hobbyists for its bright green coloration, durability, and ease of care.

However, you must provide it with reasonably clean and nutrient-rich water to help it thrive.

Bacopa may create plenty of pearl or bubbles in a moderately lit aquarium with a water temperature of 22° – 28°C.

3. Rotala

Rotala sp. H’ra or Rotala contains pointed, razor-like leaves, which produce the most beautiful pearling in an aquas­cape.

Rota­la is a hall­mark of aquar­i­um plants and is easy to grow. They offer the most vibrant appearance in tanks with higher­ light intensities.

Providing this plant with ideal water parameters can make you witness the most spectacular pearling.

Maintain your aquarium PH between 6.5 and 7.5 and a water temperature of 72-82 F to help them engage in photosynthesis effectively.

More importantly, ensure they receive at least 8 hours of high-intensity lighting to help the plant grow to its full potential.

4. Mayaca

Mayaca is a bushy plant that resembles plants like Rotala Wallichi and Cabomba. It has thin and fragile leaves and is responsible for a spectacular lush-green effect in any tank.

I recommend Mayaca to any beginner aquarist, as this is a hardy specimen with flexible water parameters. You do not have to inject your tank with CO2 to help this plant thrive.

Nonetheless, Mayaca demands a nutrient-rich environment and clean water for healthy growth. Mayaca offers the best pearling effect in moderate to high-intensity light in waters with a pH of 6.0 – 7.5.

This is one of the lowest maintenance aquatic plants for your fish tank if you wish to see pearling in your aquascape.

Buy a couple of Mayaca plants for your tank to witness the plant’s miraculous pearling capabilities yourself.

5. Micranthemum Micranthemoides (Pearl Weed)

Pearl Weed is a graceful aquatic plant with small arched leaves. It grows fast and can cover the bottom of a tank within weeks.

It goes 5-8 inches per month, making it one of the fastest-growing aquatic plants.

Aquarists seek the pearl weed plant for their tanks for its exceptional pearling capabilities.

In optimal conditions, you will find the plant producing plenty of oxygen. It gets its name from its ability to release the most mesmerizing little oxygen bubbles.

It is also an ideal plant for novices as it does not require much caretaking. Trimming the plant often and setting up your tank with an efficient LED light can help the plant produce the most beautiful pearls.


The world of fish keeping has so many little joys to offer to aquarium hobbyists, and one such awestriking phenomenon is the pearling effect caused by aquatic plants.

Choosing the right aquatic plants for your tank can offer the most scenic look and appeal, and the plant pearling effect can add a magical touch to your aquarium.

You may get lost in its beauty every time you pass your fish tank.

Get your tank a couple of pearling aquatic plants and watch the magic unfold before your eyes.

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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