How to Achieve Pearling Plants in the Aquarium

Some time has passed after your aquarium light turned on and you notice something amazing: tiny bubbles (or pearls) sprouting from your aquatic plants. Pearling plants are nice to look at, but what makes them pearl, and is it healthy for your tank? Moreover, why would a plant suddenly start pearling, and is this a sign of good growth or, perhaps, disease? Why did the pearling start to occur right after a water change?

Let's learn about what pearling plants are and what it means to have them in your aquarium.

In this article, we will answer:

1. What are pearling plants?

2. Is pearling good for my aquarium?

3. How can I get my plants to pearl?

4. What are some aquarium plants that pearl?

What are pearling plants?

To better explain, let's start with a review of how photosynthesis works. All plants produce an amount of oxygen when they photosynthesize during the day. Eventually, the plant releases the created oxygen through its tissue. Sometimes the released gas takes the form of visible bubbles that cover the plant's leaves and stem.

Typically, this happens because the aquarium plant releases oxygen faster than can be dissolved in the water in that location of your aquarium. As a result, they form bubbles that resemble small shiny pearls and the process itself is called pearling.

 
Photo credit: @aquatechbetta

Is pearling good or bad for my aquarium?

Typically, pearling shows that your plants are producing more oxygen than usual, meaning fastened photosynthesis is taking place. Many aquarists feel proud of their plants bubbling and consider it a sign of healthy plant growth. However, the formation of microbubbles itself is just a function of how saturated with gas the water around the plant is.

If there is low gas saturation in the water column, the plant will still produce oxygen even if you don't see it pearling. On the other hand, with high gas saturation in the water column, you will most likely see your plant pearling.

We should also note that oxygen is not equally dissolved in a tank. Usually, in an aquarium, there's less oxygen at the bottom of the water column. This is the reason why most plants will form pearls on the leaves near the top of the tank first.

In conclusion, all pearling plants are likely healthy, but not all healthy plants will produce microbubbles or "pearl." Whether your plants will pearl or not depends on the saturation of gasses in your water.

How can I get my aquarium plants to pearl?

To expand more on this, let's show you what the photosynthesis process looks like when you write it down. You get the following photosynthesis formula: 6 CO2 + 12 H2O + photons → C6H12O6 + 6 O2 + 6 H2O. More simply put: Carbon Dioxide (CO2) + Water + Light energy → Glucose (for the plant to feed) + Oxygen + Water.

Basically, in order to increase oxygen production in plants, you need to ramp up either CO2 injection or light intensity. That being said, here are 7 different methods to get your aquarium plants to the pearl:

1. Increase CO2 Levels

If you were a chemistry geek back in school, you'd know that CO2 (Carbon Dioxide) is way more soluble in water than O2 (Oxygen). This means that when you start injecting the Carbon Dioxide into your aquarium it quickly saturates the water with gas.

Pressurized CO2 also speeds up the rate of photosynthesis, which in turn speeds up the production of oxygen by your plants. These two mechanisms combined significantly increase the chance of your plants creating visible oxygen bubbles. Pressurized CO2 is likely the best way to encourage pearling in aquarium plants.

• New to the high-tech game? Check out this article on How to Add CO2 to Your Planted Aquarium HERE

2. Increase Light Intensity

Many great aquarium lighting brands, such as ONF lighting, have adjustable light intensity. You can also purchase a light dimmer for LED lights that do not have a dimming capability built-in. Ramping up light intensity could easily increase the rate at which photosynthesis is happening. Typically, more light means a higher chance of your aquatic plants pearling. 

Note: Any increase in light intensity should be gradual so that your plants can adapt. Moreover, if your tank receives more light than what your plants can consume, then you may encourage all types of algae to appear. Some forms of algae such as Black Beard Algae are notoriously difficult to remove.

3. Do a Large Water Change

Sometimes you can witness your plants pearling right after you did a huge water change in your fish tank. This happens because tap water is usually saturated in gas. Therefore, adding enough new tap water to your planted tank stimulates plant pearling.

This could also happen when changing aquarium water with RO water (Reverse Osmosis water). That's because some aquarists keep their RO water in reservoirs with circulation pumps. Moving water holds more gas than standing water, hence is more easily saturated.

Note: Many aquarists call this phenomenon "fake pearling." However, since it happens for the same reason as the "genuine" pearling, we don't agree with that label. 

4. Increase Water Temperature (If You Can)

Tropical tank owners are more likely to see their plants pearling. This is because warm water typically holds less gas than cold water and is therefore saturated more easily. Increasing the water temperature in an aquarium can support pearling, but only do that if your plant species and fauna can tolerate it.

5. Add More Aquatic Plants

Having a densely-planted tank increases your chances of witnessing the beautiful phenomenon of the pearling garden. That's because when you have a lot of aquatic plants in your aquarium, you're essentially creating an oxygen-producing machine. This saturates the water around your plants with oxygen much faster, which in turn helps with pearling.

6. Reduce Water Flow

If you have powerhead pumps or other devices that create a current inside your aquarium, then you are less likely to see pearling. Strong currents have nothing to do with the rate at which your plants produce the oxygen bubbles. Instead, it's simple mechanics - the bubbles may get blown away before you're able to notice them. It's often the case to see your plants pearling if you turn off the aquarium's filter for an hour.

7. Trim and Replant Your Plants

Trimming and propagating your stem plants especially will not only result in a fuller look in your scape but will also encourage new, healthier growth on the trimmed plants. It's very common to see aquatic plants "pearling" after they've been freshly trimmed. Although, this is considered "fake" pearling because that's simply gas being released from the cut stems and leaves. This will appear as a stream of bubbles flowing from the severed stem as opposed to pearl-like bubbles resting atop the leaves.

Tip: If you want to see your plants pearling without CO2 injection, then try the following: 1. Trim all plants that need it. 2. Do a 30% water change. 3. Turn off the filter and powerheads. Wait for a couple of minutes and be ready to take a picture because it will be glorious.

Aquatic Plants That Pearl Like Crazy

Naturally, some plants produce more oxygen than others and are therefore easy to get to pearl. These species still require good growing conditions for this to happen but once it does you will be left in awe. Here are 5 of the best stem plants for pearling:

1. Rotala H'ra

Rotala sp. H'ra is a semi-demanding plant that is a colorful addition to high-tech planted tanks. Under the right conditions, it can display a nice contrast of reddish-orange and a bright red stem. Like all Rotalas, once you get it pearling you won't be able to stop it because it produces a lot of oxygen when happy.

2. Mayaca Fluviatilis

Mayaca Fluviatilis is one of the best aquatic plants for a pearling aquascape. The delicate leaves of this plant create a spectacular bright green bush when grown in large clusters. It gives off bubbles like there's no tomorrow and it's not that difficult to keep either.

3. Micranthemum Micranthemoides (Pearl Weed)

Micranthemum Micranthemoides, also known as Pearl Weed for its excellent pearling, is another plant that when grown in optimal conditions will produce a lot of oxygen. It's also ideal for middle-ground aquascaping and is suitable for beginners in the hobby. This 'stem plant' can also be grown as a carpet plant. In order to achieve a Pearl Weed carpet, trim often and provide strong LED lighting and CO2 injection.

4. Bacopa Monnieri

Bacopa Monnieri, or Moneywort, is a well-known aquatic plant with easy care requirements. Bacopa is perfect for filling space and adding dimension to any aquascape because of how fast it grows. This plant is great for beginners because it does not require CO2 and can be easily grown both emersed and submerged.

5. Riccia Fluitans

Riccia Fluitans, also known as Floating Crystalwort, is a stunning plant that pearls like crazy once it's established. By nature, it's a floating aquarium plant, but it can be used in various aquascape scenarios, such as attached to hardscape like moss. It can also be modeled to grow as a carpet or a bush. Although, a good plant weight is needed to anchor it down.

Tell us - Have you experienced pearling plants in your aquarium before? If not, would you like to one day? Comment your thoughts!

If you have any questions regarding this article, please DM us on Facebook or Instagram so we can assist you! @buceplant