Hornwort Plant – A Complete Care Guide

Some plants can transcend the usual expectations of aquarists and slide into multiple roles at the same time.

Hornwort is one of those few plants that can give you complete freedom to design your aquarium and at the same time the ability to use it to oxygenate the water and provide shelter to your fish. The growth rate of this easy plant is fast and growing it as a beginner is simple and smooth.

All you need is factual information with some useful tips to start. In this care guide, I will show you what to expect from the Hornwort plant and how to help it fight against the odds.

Key Takeaways

  • Hornwort is a low-maintenance, beginner-friendly, and pretty hardy plant to grow in a home aquarium
  • They are invasive plant species because of their high versatility rate and allelopathic qualities
  • They grow best as floating plants and can control algae growth

A Brief Overview Of Hornwort Plant

Scientific NameAnthocerotophyta
Common NamesHornwort, Foxtail
FamilyCeratophyllaceae
OriginNorth America
Skill LevelEasy
LightingModerate
Tank PlacementBackground
Flow RateModerate
Temperature Range59 F° to 86 F°
Height120 inches
pH Range6.0 – 7.5
Growth RateFast
Feed TypeWater column feeder
Co2 RequirementNo

Hornwort Introduction

Hornwort is a well-known and one of the oldest aquatic plants that you still find in home aquariums and in the wild around the world.

They are scientifically recognized as Ceratophyllum Demersum while commonly known as either Hornwort or Foxtail. They belong to the Ceratophyllaceae family from the genus Ceratophyllum.

This hardy plant makes an ideal candidate for most aquariums, especially those that are run by beginners. Since Hornwort is highly skilled when it comes to adaptability, it can easily spread to new regions as an invasive species.

But that happens mostly in the wild so there’s nothing to worry about. Instead, we will focus on how this plant can be an exceptional addition to your aquarium due to its appearance and resilience.

Origin And Habitat

Hornwort plants are native to South America though they are now available in every continent except Antarctica.

They were first introduced to the world by a Swedish botanist named Carl Linnaeus. There are only 100 to 150 species available, although you can find 300 species names published due to misidentification.

In the wild, this hardy plant grows on damp soil and can put up with a diverse range of conditions. This includes growing in tropical waters, as well as cold water temperatures, low lighting conditions, and even polluted environments.

Is Hornwort Invasive Species?

Due to its versatility, ability to grow under various conditions, and easy propagation, the Hornwort can quickly turn into an invasive species.

But this is not the only reason they have a high potential to spread to other zones. Hornwort has allelopathic qualities, which is a phenomenon where plants with these biochemicals slow down or entirely prevent the growth and survival of other plants.

What Does Hornwort Look Like?

Apart from displaying qualities that help you maintain a healthy tank environment for your fish, Hornwort looks incredible in almost every aquarium setting.

Hornwort

Generally, Hornwort looks dark green to yellow depending on the light intensity and water temperature. If the temperature is warmer, the plant will appear yellowish-green. But if it is kept under its preferred condition, you will see a dark green shade.

Hornwort doesn’t have true roots. It grows rhizoid (hair-like roots) which acts and functions like roots so the plant can stay intact in the substrate. Some people feel like the main stem grows multiple plants. But when you observe it, you notice that one plant grows multiple side shoots, creating the look of many plants.

When it comes to Hornwort leaves, they look dark green and are not completely smooth. The texture is somewhat bumpy. The leaves are tiny and are produced around the stem in a set of 6 to up to 12. The base comprises loosely packed and larger leaves, while the end has shorter and tightly attached leaves.

Stems are usually 2 inches in diameter, but they can go as tall as 2 feet. To prevent Hornwort from running over your tank, keep it properly maintained.

It is essential for Hornwort to produce flowers for reproduction. Hence the flowering plant will feature different colored flowers that are deep red, pink, or brown. The shades can vary depending on how strong or low the light is. These flowers bear an ovoid fruit that is typically 0.16 inches in size.

Placement And Lighting

Hornwort can be placed in two different ways, each with its benefits.

This fast growing plant is commonly used as a background plant because of its huge size. But if you have a larger tank, you can also use it as a mid-ground plant.

Since Hornwort is a floating plant that can also survive when planted in the substrate, I will recommend you consider what types of fish you have in your tank. Small fish love floating plants because they create a dense mate overhead.

These mats block out light and keep the fish safe and make them comfortable. The surface dwelling fish will also love to see Hornwort floating on the water surface because they get to interact with them by weaving from stems to leaves and back.

As far as lighting goes, Hornwort doesn’t need too much light to grow. The plant already grows rapidly, making it challenging for planted tank owners to prevent it from growing to new locations. If you keep it under intense lighting, the plant might start growing even faster.

You can go for LED lights to give them medium lighting conditions. Keep the duration under 12 hours per day. But do not deprive the plant of proper lighting as it will impact the color of the plant.

Can Hornwort Grow Floating?

Even though with a versatile plant like Hornwort, you get plenty of freedom to decide its placement, the best way to grow Hornwort is as a floating plant. Because this way, this great plant gets finer access to light and carbon dioxide from the air. Also, you don’t have to make arrangements for it to float on the surface since the plant can float naturally.

It is possible to grow it by rooting it in the substrate or attaching it to a hardscape. But since Hornwort doesn’t have a strong root system, it will likely decompose.

What Are Good Tank Mates For Hornwort?

Compatibility is never an issue with Ceratophyllum Demersum since it is hardy and good to pair up with a wide range of fish and plants.

It has a high potential to survive nibbling even in a goldfish tank and become a source of food for adult and baby fish.

It’s still better to know what species make good tank mates in Hornwort planted tanks.

Ideal Tank Mates

Hornwort is surprisingly compatible with herbivorous fish because its leaves don’t appeal to them. The rough texture will prevent the fish from nibbling on it.

You can pair them up with fish like:

Snails like Nerite snails, Japanese Trapdoor snails, and Mystery snails are also good options to consider for Hornwort plants.

If you want to introduce shrimp in a fish tank inhabited by Hornwort, you can go for Red Cherry Shrimp, Black Rose, Blue Velvet, Green Jade, and Rill Shrimp.

The floating Hornwort plant will function as a refuge for most livebearers whenever they are mating. They will also provide small fish with shade and block out light that disturbs the day-to-day activities of fish species.

You can feel free to choose snails and shrimp from my suggestions to get help with cleaning up any plant debris. Hornwort sheds leaves, usually as a result of getting nibbed by aggressive and hungry fish. Snails and shrimp will clear up the bottom, preventing decomposing plant matter from polluting the tank environment.

Compatibility with Plants

If you want to grow plants alongside Hornwort, make sure you know about its allelopathy nature.

Hornwort grows fairly fast by readily devouring nutrients from the water. This helps prevent algae growth. But since Hornwort can outcompete new plants as well as those that don’t quickly devour nutrients, it is very likely that your other plants will suffer from the lack of nutrients. This will not kill the plants, but it can surely slow down their growth rate.

Another essential thing to consider is what plants will be under this great floating plant. Hornwort blocks out light, which can be an issue for those plants that need intense lighting.

You can choose Java Fern, Anubias, Java Moss, Sagittaria, and American Water Weed for Hornwort planted tanks. These plants don’t need intense lighting to survive and can withstand Hornwort.

But avoid planting Duckweed as it has a faster rate of consuming nutrients.

Fish Species to Avoid

Like fish that get along well with Hornwort, there are some species that will damage the plant when they are hungry.

Fish species like African Cichlids, and Goldfish are not recommended to put in a fish tank where you have planted Hornwort.

As long as you feed your aggressive fish on time, the plant will sustain minor attacks on the leaves. But if your Goldfish is too hungry or your African Cichlid isn’t in a good mood, they will likely attack it too aggressively, resulting in serious plant damage.

Feeding Hornwort (Fertilization)

The plant doesn’t need additional fertilizers to grow though occasional doses will make it fuller and healthier. You can go for Nitrogen and iron-based fertilizers for Hornwort to develop strong and fuller leaves and optimal coloration.

Hornwort grows incredibly fast by soaking up nutrients. If you choose to add fertilizers, other plants in your aquarium tank will highly appreciate it.

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But since it has a reputation for eating up nutrients faster than other plants, you may need liquid fertilizers for your tank so that other plants don’t starve to death. Add fertilizers at least once a week to make up for the loss of nutrients.

Pro Tip: Keep an eye out for nutrient deficiencies in your plants. The signs include leaves turning yellow, shortened internodes, and abnormal leaf coloration, such as bronze or purple leaves.

How Much and How Often to Feed?

The quantity and frequency of feeding depend on the number of plants and their individual needs. If your tank is heavily planted, then feed your plants accordingly. Keep factors like CO2, lighting, filtration, and maintenance in mind.

A planted tank should have higher numbers of nitrates so that the plants don’t have to compromise on the number of nutrients. And it becomes more essential when you have Hornwort.

Author's Note: If you have shrimp, make sure you don't overdo fertilizers and CO2. Some fertilizers have copper, which makes them lethal for shrimp and even Hornwort. Do your research!

CO2 Injection

As I mentioned above, you don’t need to add extra CO2. Medium access to carbon dioxide is enough for the plant to grow.

If you have a heavily planted tank, go for a higher dose of CO2. But in a small tank with limited plants, CO2 can trigger the already fast growth rate of Hornwort, which can be extremely challenging to handle.

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Hornwort Care

Managing Ceratophyllum Demersum is easier than you think. It doesn’t matter whether you have any prior experience or you are a total beginner. You can take care of the plant fairly well.

First thing first, always do occasional trimmings and pruning. It ensures the plant doesn’t have massive growth and stays out of the lane of other plants.

How your plant grows will depend on how and where you trim it. For example, if you trim it from the main stem, it is likely that Hornwort will grow more from the sides. This will eventually lead it to have its branches out. But if you trim the sides, Hornwort will grow straight and stronger.

It can grow under medium to strong lighting. However, it is better to expose it to bright lighting so it can have optimal growth.

Planted Tank Parameters

Thanks to the hardy nature of Hornwort, these species can tolerate a wide variety of tank setups and temperatures.

In the wild, Hornwort grows in lakes, ponds, rivers, and marshes. They get to deal with different environments where water parameters vary.

Also, their versatility makes it easier for aquarium owners to grow them in small and large planted aquariums. When pruned regularly, Hornwort will fit in your small tank. But if you don’t trim it on time in a large tank, that will also be completely fine.

Hornwort needs at least a 15-gallon tank to thrive. Water temperature is one of the most important factors for proper growth. Expect it to grow 0.4 to 0.8 inches a day under its preferred temperature.

Keep water temperature 59 F°-86 F°, water hardness 5 to 15 dGH, and pH 6.0 to 7.5 to keep your plant healthy.

Filtration

Hornwort doesn’t need a strong filtration system as a natural oxygen booster.

But keeping water quality up to the mark is recommended. You should make water changes once a week and remove plant matter from the tank whenever Hornwort sheds leaves.

Other than that, I recommend getting a sponge filter, hang-on-back filter, or canister filter to weed out unnecessary toxins like ammonia, nitrates, and nitrites from the tank.

Pro Tip: Don't plant it close to a filter inlet so that it can stay safe from getting blocked by plant debris.

Flow

Hornwort prefers a gentle flow. While planting, make sure the needles don’t get stuck in the filter intake and disturb the water flow.

If the flow is too light, the fish that love medium flow will likely get stressed. Low flow will also influence your plant’s growth, making it appear bushier. But if it’s too strong, your plant will likely grow tighter together, while the fish that prefer medium water flow will also get disturbed.

How to Propagate Hornwort

Producing new plants is not a big deal for Hornwort.

The propagation happens through vegetative fragmentation. This method is widely used for invasive species. All you need to do is stop trimming for a few weeks.

Only separate one part of the plant from the rest and take the cuttings (video source) where the flow is low to moderate. After that, let it grow on its own. You don’t have to plant it; free-floating is the best way to propagate Hornwort.

You can either get a whole stem or only a small part from the main stem. The main stem grows multiple side shoots or, in autumn, buds. In their natural habitat, they form buds that sit on the ground when the weather is cold. Once the temperature gets warm, the buds start sprouting. These buds then turn into a new plant.

Another way to get multiple Hornwort plants is by cutting off the new growths of the plant and letting it grow. If you don’t have extra trimmings, you can ask around.

Health And Disease

There are countless benefits of introducing Hornwort to your fish tanks. But sometimes, the plant can become a hassle for those who don’t meet their basic needs.

Hornwort is famous for shedding needles or its needle-like leaves. It usually happens when there are huge water fluctuations or environmental changes. It can also happen due to a lack of nutrients or feeding it chemicals like liquid carbon.

The plant will go through normal shedding when you first introduce Hornwort to your tank. Once it gets used to the new environment, it will recover. But if the shedding doesn’t stop, you need to maintain the number of nutrients in the water or allow the plant to sit under intense lighting.

Another disease is Hornwort turning bronze. Even though the plant does well when the lighting is high, extreme lighting can influence the leaf coloration, causing it to turn brown from the tips. Sometimes warmer temperatures can also alter the color of the leaves.

Signs Of Health In Hornwort

A healthy Hornwort plant should be bushy, with its stems covered by thick needles. The color should be deep green, with the exception of the nips. Nips can take on a lighter shade of green. The needles are typically thin and stiff.

Apart from this, a healthy Hornwort will display long branches or side stems.

Where To Buy Hornwort?

Hornwort is really famous and, therefore, widely available. You can purchase them online or get them from any pet store or fish store.

The plant is sold in bunches. A bunch of 3 shouldn’t cost more than 8$. Finding new trimmings online can be tough since they don’t survive shipment well.

FAQs

Can Hornwort Hurt Fish?

Hornwort plants have a good compatibility rate with lots of fish species. But they can damage the delicate fins of Betta fish. If the leaves are rigid, depending on how old your plant is and under what water conditions it lives, the roughness can tear the fins of a Betta.

Is Hornwort A Good Oxygenator?

Hornwort is one of the best plants that you can use to oxygenate your aquarium water. Aside from giving thick foliage to the baby fish to use as a hideout, it promotes oxygenation. Hornwort also prevents the growth of blue green algae that is considered extremely harmful to fish tanks.

Is Hornwort Easy To Grow?

Hornwort is a beginner-friendly plant that grows rapidly under favorable conditions. If there’s enough light and nutrients, Hornwort will grow very easily. The typical growth rate is 1 to 4 inches per week.

Closing Thoughts

While it’s true that not all fast-growing plants are easy to care for, hornwort is a great example of a fast-growing plant that is appropriate for beginners. If you’re looking to add some greenery to your home but don’t have a lot of time or experience with plant care, hornwort may be the perfect option for you. Have you kept Hornwort before? Let us know in the comments how it went for you or if you have any other beginner-friendly recommendations.

by Mark

Mark is the founder of Aquarium Store Depot. He started in the aquarium hobby at the age of 11 and along the way worked at local fish stores. He has kept freshwater tanks, ponds, and reef tanks for over 25 years. His site was created to share his knowledge and unique teaching style on a larger scale. He has worked on making aquarium and pond keeping approachable. Mark has been featured in two books about aquarium keeping - both best sellers on Amazon. Each year, he continues to help his readers and clients with knowledge, professional builds, and troubleshooting.

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