Why Do Aquarium Plants Pearl – With 5 Great Examples

Sometimes my aquarium plants produce a long trial of tiny bubbles, and to me it mostly happens after a water change. This is called “pearling” and I did not know when it happened or what caused it. Therefore I had to find the answer.

Why do aquarium plants pearl?

Aquarium plants pearl when they are producing oxygen at a higher rate the water can absorb through diffusion. It is an indicator that photosynthesis is working overtime and the plant is healthy, but a plant that does not pearl can also be healthy.

Now that you know why plants pearl, it is important to learn what it means. I also like the sight so I want to help you get a plant to pearl by giving some tips. I’ll briefly go over some of these points in the rest of the article.

How to get your plants to pearl

If you’re trying to make your plants pearl, you’ve got to increase on some factors to make sure they are growing near their maximum rate. To do this, the aquarium plants need a lot of light, plenty of fertilizers and a lot of CO2.

Some slower growing plants like Java Ferns or Anubias plants are unlikely to pearl. If you are looking for plants that pearl easily, make sure you get fast growing stem plants. An example would be Anacharis Elodea, Moneywort or Sunset Hygro. However, these are just examples, and this is the rule of thumb: the thinner the leave the easier the oxygen can escape.

Make plants pearl temporary

If you want your plants to pearl for a show, to take pictures or to shoot great video, there is a trick. If you’re lucky and your tap water contains a lot of CO2, your plants are likely to pearl after a big water change. This is because there is a surplus of carbon-dioxide which gives the photosynthesis a boost.

When your tap water does not hold that much CO2, you can buy a big bottle of carbonated water in the store, and add that to your aquarium. In both cases plants are likely to pearl within 20 minutes.

This can give great pictures like this one.

Why are your plants not pearling

If you’re adding a lot of CO2 and have bright lights, but your aquarium plants are still not pearling, here is what’s up. Your plant is still not able to produce oxygen at a high enough rate to pearl, and that’s because of a deficiency in either light, CO2 or nutrients.

I would also look at what plants you are growing and trying to get to pearl. Plants with thicker leaves are harder to pearl, whereas stem-plants are easier. Also, I would recommend raising the CO2 first, because raising the light increases the risk of algae growing.

Finally, make sure you’re providing sufficient nutrients in the form of liquid fertilizer. If the plant has enough light and CO2, it needs enough nutrients to be able to facilitate the rapid growth. When you’re really going for maximum growth-speed, you most likely have to dose more than the daily/weekly dose of your fertilizer.

Are pearling plants healthy?

In general, plants that are pearling by themselves (without giving a CO2 boost) are very healthy and are growing rapidly. However, pearling is not a must for plants to do well. In you’re looking for the pearling effect, chances are you are constantly raising the amount of light or CO2, which could cause algae to grow too.

Instead, you should be looking for healthy plant growth in your tank. All the plants that are growing are healthy. If they’re not pearling it means there is a part of the plant triangle (below) that’s lacking, but if there still is a balance I would prefer that scenario.

This is why I, even though I love the aesthetic effect of pearling, would call pearling overrated. It’s not something I recommend you strive for when keeping live plants, unless you’re experienced and know how to circumvent an algae explosion.

This is a common misunderstanding around pearling plants

While doing the research for this short article, I looked through lots of forums and Facebook groups to find out what other people thought about pearling. It came to my attention that a lot of people thing pearling has to do with the concentration of dissolved oxygen in the water.

People think that plants pearl when the aquarium water is fully saturated with oxygen, and therefore the oxygen produced by the plant has nowhere to go but to form bubbles. This can not be the case, because then how would plants be able to pearl in a massive aquarium?

It’s possible that one small plant pearls in a giant tank, and in that case there is no way that all the water is completely saturated with oxygen.

Instead, plants pearl when they are producing oxygen at a higher rate than the water can absorb. It’s all about how quick oxygen can dissolve in water, and if a plant is producing more oxygen, it will start to form bubbles.

5 Aquarium Plants That Pearl Quick

1. Mayaca fluviatilis

Around three years ago, “burr740” uploaded this picture on this thread on a forum. When asked what plants pearl the quickest, he uploaded this picture of a plant called “Mayaca fluviatilis” and it looks almost white with all the oxygen bubbles! The plant is located among many other plants in this tank, so it definitely is one of the plants that pearl quickly when give the right parameters.

2. Bacopa Caroliniana

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On the same forum thread, a user with the username “jellopuddinpop” shared that his “Bacopa Caroliniana” was an easy plant to get to pearl. Because of this first-hand experience it definitely deserves a place on this list.

3. Rotala Rotundifolia

On this thread on the PlantedTanks forum, Dempsey shared pictures of his plant that was pearling. This post was placed all the way back in 2013, unlike what smartphone is best, this information still is relevant today.

4. Anacharis Elodea / Elodea Densa

While I did not take photos, I got this plant to pearl as my first pearling plant ever. It’s a great beginner stem plant that will provide a lot of oxygen in your aquarium.

5. Moneywort

Another recommendation is a plant called Moneywort. This plant is on a lot of easy, fast growing plant-lists, and it also deserves its place here. A great fact about moneywort is that it continues to grow outside the aquarium once it’s reached the top.

While these are 5 plants that are known to pearl easily, there are many other plants out there that you can get to pearl. Essentially every plant can produce oxygen at rate high enough to form oxygen bubbles.

If you want to strive for this, by all means go ahead, just know that your plants are healthy when they show good growth, and pearling is just a pretty side-effect. Chasing this effect can cause algae and may require insane amounts of injected CO2. However, when plants finally start to pearl, it’s worth it!

Video explanation

I’ve also created a Youtube video on this topic. If you prefer watching and listening over reading, make sure to check it out.

Bart Sprenkels

I have been keeping multiple aquariums since I was 18 years old. Just like many of you, I started with two goldfish but quickly learned they were not suitable for aquariums. Later, I switched to a tropical community tank and I also have two pet musk-turtles in a bigger aquarium. You can read more about me here.

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