Pearl Weed – A Complete Care Guide

Welcome, follow plant keepers 🌿!

Carpet plants are great for aquascape but are the type of plants that can require a ton of care (and CO2) to thrive. The subject of this blog post today, Pearl Weed, is a good compromise of a great-looking carpeting plant that needs moderate but not extreme care to thrive.

I’ll go over all it takes to be successful with this plant and keep you from having issues. Let’s get started right away!

Key Takeaways

  • Pearl weed does best with CO2 if your goal is to create a carpet
  • It is best as a foreground plant due to its small height
  • It does well in a nutrient-rich environment and requires moderate to intense lighting

A Brief Overview of Pearl Weed

Scientific NameHemianthus micranthemoides
Common NamesPearl weed, Baby tears, Pearl grass, Amano pearl grass
OriginNorth America
Skill LevelEasy
LightingModerate to high
Tank PlacementForeground, midground
Flow RateModerate
Temperature Range66 F° – 82 F°
Height2 to 5 inches
pH Range6.5 – 7.5
Growth RateModerate
Feed TypeWater column feeder
Co2 RequirementRecommended


Pearl weed is popular around the world for its bright green color, high coverage growth, and ability to decorate your tank in different ways.

It scientifically goes as Hemianthus Micranthemoides, commonly known as Pearl Weed, Baby Tears, or Pearl Grass.

It belongs to the Scrophulariaceae family from the genus Hemianthus. When left on its own, it can create a dense carpet for the base of your tank.

Origin And Habitat

Pearl Weed originates from Florida and can be found growing in damp areas in its natural habitat. They are used to thrive in moving waters where the substrate is either made up of gravel or sand.

They were found by an English botanist and zoologist, Thomas Nuttal, almost 2 centuries ago. They are pretty old plant species compared to other aquatic plants.

They are often mistaken for Hemianthus Callitrichoides due to their slightly similar appearance. We will go over what sets Pearl Weed apart from the other species later.

What Does It Look Like?

Apart from being easy to care for, Pearl Weed lives up to your expectations of making your plant beautiful to look at. 

Pearl Weed

Pearl weed looks bright green in color. This looks amazing in contrast with red or deep backgrounds and plants in aquariums.

It grows thin green stems and can be used for different spots of the tank. The stems are delicate so make sure you are careful while planting them into the substrate.

The leaves are small and narrow and have a compact setting. They are usually 1 cm to only 0.4 inches long that grow in whorls of at least 3.

In suitable conditions, it forms dense bushes and produces side shoots. These shoots are usually horizontal, but you can see them growing vertically with larger gaps or internodes between the leaves under low lighting.

Pearl weed is an extremely fragile plant with thin green-colored stems. If you want to carpet it, increase the light, and it will turn into a dense carpet. Other than that, frequent trimmings are necessary so it can branch out new sheets more frequently.

One of the good things about getting a Pearl weed is that it can tolerate substantial pruning. You can make arrangements depending on how you want to see it in your tank. You can make regular trimmings to prevent it from growing vertically. But if you want to use it as a background plant, leave Pearl Weed on its own to grow. Also, if you trim it on a regular basis, it will encourage the spread of runners horizontally.

Since Pearl Weed is pretty easy to manage, you can use it for foreground coverage, too.

Aquarists who are always on the hunt for finding plants that provide fish with thick coverage during breeding seasons can use Pearl weed completely risk-free.

Difference Between This and Monte Carlo

When your goal is finding a carpeting plant, both Pearl Weed and Monte Carlo are good to go with.

Since both plants are pretty popular as carpeting plants in the hobby, they are often mistaken for each other.

Both plants can form a dense carpet for the bottom of your tank and are easy to maintain. They also need proper conditions for optimal growth, but there’s a difference between them. Pearl weed has very delicate roots, while Monte Carlo stays on the stronger side in the hobby. The strong root system of Monte Carlo allows it to avoid getting easily uprooted.

Also, you will see Pearl weed growing very rapidly vertically. And even if you trim it on time, maintaining it as a carpet is slightly challenging compared to Monte Carlo. Overall, Monte Carlo is an easier plant to grow and care for.

Placement And Lighting

The high adaptability of a Pearl weed helps you decide where and how to place it in your aquarium.

You can grow it as a background plant, use it for the mid-ground area, and even place it with other small plants in the foreground section of your tank. The growth will entirely depend on how often you trim it, which will also influence its position in the tank.

If you have carpet in your mind, pruning it will help with creating a lush green carpet in the foreground of your aquarium.

Pearl Weed grows nicely when attached to driftwood. If you want to use it as a background plant, you can use CO2 injection that will trigger its bushier growth.

Though growing it as a carpet might be tough for beginners and intermediate tank owners since it naturally grows vertically. You can take out one stem and carefully place it horizontally into the substrate so spread across and create a beautiful carpet.

And as for lighting, the plant grows best when you keep it under sufficient lighting. A weaker access to proper lighting can disturb its growth rate, resulting in internodes between the leaves, more delicate roots, and discoloration.

What Are Good Tank Mates For Them?

Pearl weed can get along with a wide range of fish species.

Even though it has delicate roots, Pearl Weed acts like a hunter when it comes to absorbing excess nutrients. It is also a good option to consider for providing your fish with a safe place to hide.

Oxygenating water and functioning as a buffet of biofilm for the newly hatched fry and shrimplets are some other benefits you can get from a Pearl Weed.

Ideal Tank Mates

Pearl weed plants are compatible with the following fish:

If you want snails to introduce to your planted tank, ramshorn snails, nerite snails, black devil snails, and japanese trapdoor snails are some of the best options to consider.

For shrimps, you get a variety to choose from. Red Cherry Shrimp, Snowball Shrimp, Blue Velvet Shrimp, and Green Jade are some of my recommendations. Amano shrimp and Crystal Red Shrimp can also be great to pair up with a Pearl weed. In fact, the presence of Pearl weed will encourage most shrimp species to inhabit your tank.

Since this light plant grows a thick green carpet, most small fish will love to have them in their tank. It can work well as a cover for your small pet against intense lighting and aggressive fish species when grown as a background plant.

Fish Species To Avoid

Pearl Weed can nicely withstand minor attacks of fish. But some species are too aggressive to put in planted tanks.

Avoid species like Goldfish, Jack Dempsey, Clown Loaches, Koi fish, and African Cichlids.

Most species from this list will hungrily attack the plant unless you use it as a floating plant.

Feeding And Fertilization

Pearl weed is known for growing incredibly fast in its natural habitat. And when kept in optimal conditions in a home aquarium, these plants grow large and strong on their own.

Generally, Pearl weed is a water column feeder. It needs a protein or nutrient-rich substrate to thrive. This makes it a great choice for aquarists who want to make the underwater environment safe for their pet. Since this stem plant doesn’t have any strong root system, it mostly absorbs nutrients through its leaves. Therefore, I will recommend using liquid fertilizers instead of root tabs.

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As I mentioned earlier, because of the frail root system, a Pearl weed’s growth and survival depend on regular doses of liquid fertilizers. The occasional addition of fertilizers will ensure that the plant stays safe from suffering from turning yellow and malnutrition. It can help encourage the plant’s super-dense growth as long as they are fed plenty of fertilizers.

How Much And How Often to Feed?

The cycle of feeding your plants mostly revolves around how dense your planted tank is. And with each plant having its own individual needs, you need to make a routine that suits all of them.

As a general rule of thumb, you should feed your plants twice a day in a small amount. The frequency might alter if you perform frequent water changes and dose CO2.

You can also get a nutrient-rich substrate. Pearl weed will grow best in the dirt since it has lots of nutrients. Apart from that, it fits the needs of the plants related to when and how much they want to consume.

CO2 Injection

Apart from being one of the most uncomplicated plants for novice planted tank owners, Pearl weed has a high chance of growing without CO2 in low-tech tanks, as well as high-tech tanks.

But supplementing it with CO2 can improve the growth, help it grow faster, and facilitate pearling. Still, that’s totally optional. Pearl weed can already go big faster than other aquarium plants even with its delicate roots.

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Specific Care

Knowing what works best for your plants helps in the long run. You can always make arrangements for your plants and take precautions to ensure they stay healthy and thrive, even if there are minor water fluctuations.

Pearl weed can adapt to a range of conditions, given you feed it on time and keep it with compatible fish species. However, it has a high chance of overrunning your tank if you don’t trim the foliage on time. Without constant pruning, the plant can turn into a thick bush. To prevent it from overrunning your tank, all you need is occasional trimmings.

If you’re using it as a foreground plant, you will need to work harder to keep the growth under control. Intense trimmings will also encourage dense growth and proper formation of side shoots. And compared to other carpeting plants, this one will be easier to maintain.

Also, its growth rate and capability to survive solely depend on the availability of nutrients, the intensity of light, and CO2 supplementation. Apart from these, maintaining proper water temperature is also beneficial for the plant.

Pro Tip: Trim it only when it's at least 2.5 inches or 6 cm so you can create a beautiful carpet.

Planted Tank Parameters

Even though Pearl weed is a low-maintenance plant, maintaining its bright green leaves and dense growth with a delicate root system is possible. You need to know how many fluctuations in water it can withstand.

It can grow a dense mat in stagnant waters in the wild.

Pearl weed needs a 10-gallon tank to grow. Apart from exposing it to intense lighting, set water parameters that align with its needs. Keep the water temperature between 66 F° to 82 F°, water hardness around 1 to 15 dGH, and pH range 6.5 to 7.5.


Keeping water clean is essential when you have a pearl weed in the tank. Apart from making regular water changes, you should invest in getting a good-quality filter to weed out toxins before they pile up in the tank.

I recommend getting a canister filter to control ammonia, nitrate, and nitrite levels.


Despite its frail roots, the plant prefers water with enough movement. 

Keeping it in water that is still or has a very rapid flow will stress out the plant. In fact, if you keep it in water with a stronger flow, you might damage the delicate stems.

So make sure you keep the flow moderate.

How To Propagate

You can boost the population of this stem plant through vegetative propagation.

Start propagating by trimming the ends of the stems. Be careful while trimming the stems since they are quite weak and prone to damage. After that, make several bundles and place them into the substrate.

The adult plant will regrow, while the new plants will root in the substrate and sprout new shoots under good aquarium conditions.

Pro tip: While burying the stems into the substrate, make sure that the foliage doesn't cover them

Health And Disease

There are a few problems associated with Pearl weed. If you understand how to protect your plant by taking proper measurements on time, you can minimize the potential of running into adverse situations.

Melting is one of the biggest problems with Pearl weed. It usually happens when you shift it from an emersed to a submersed environment.

This environmental transition triggers a negative response from this species. The first thing you will notice is the shedding of leaves. This will last a few weeks before you see your plant adjusting to the new environment. This is more common with stem plants, so it’s okay to see them going through this temporary phase.

Another common problem with a Pearl weed is the difficulty plant. The fragile root system of Pearl weed often makes it a hard species to plant. If you try too hard, you are very likely to damage the stems. But if you are too light on the plantation, it will begin floating.

Yellowing leaves are yet another common disease in them. In dim lighting, it will have upward growth. And if the pH levels are too high or they are low on nutrients, the leaves can turn yellow.

Signs Of Good Health

A healthy Pearlweed will display fuller green leaves without too many internodes.

The stems will stay the same, though.

Where To Buy?

Pearlweed is a pretty old and famous species in the hobby. There are plenty of online stores that offer competitive prices.

Pearl Weed

A carpet growing plant that is fast growing and will do well in low light

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It shouldn’t cost more than 6$ per lead bunch.


Does This Type of Fish Grow Fast?

This species does not grow rapidly, at least until it takes hold. Though it is adaptable, you need to give it some time and provide it with intense lighting, a healthy fish colony, a nutrient-rich substrate, and sometimes CO2 to improve its growth rate. Once the species gets used to the new environment, you will have to make regular pruning every week.

Is This A Carpeting Plant?

It’s not difficult for a versatile species like Pearlweed to grow as a carpet and sit in the mid-ground or background. It takes it 2 to 3 months to turn into a carpet for a small tank.

Are They Low Tech?

Pearl is ideal to grow in a low-tech tank with proper trimming, light, water parameters, and nutrients. It is a low-maintenance alternative to other aquarium plants for beginners who don’t want any hassle.

Closing Thoughts

Pearl Weed can be a beautiful and unique addition to any freshwater aquarium. With the right care, it can carpet the bottom of your tank in no time! Although Pearl Weed may require some extra attention at first, regular grooming, good lighting, and CO2 will help this plant thrive. Do you have experience keeping Pearl Weed? Let us know in the comments below!

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