How To Care for Hornwort: A Complete Fact Sheet, Care Guide, Growth, Maintenance, and Plant Profile

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Though the name isn’t exactly lovely, Hornwort is one of the easiest and prettiest plants you can keep in your aquarium. 

They’re naturally lovely with flowy, feathery arms, and spring-like green leaves that flutter in the current inside the aquarium. 

And since they are so easy to care for, hornwort aquarium plants are especially great for beginners, though pros love them, too.

hornwort care guide

Quick Overview Facts on Hornwort

Hornworts are named for their horn-shaped spore capsules. These slender capsules, which shoot upward, are where the plants grow and shed their spores. 

These native plants grow all around the world, mostly in damp, humid places.

They’ve been introduced in many countries, including New Zealand, where they flower and spread across the lakes and rivers in thick sheets of what looks like green tissue – a thallus.

These unique plants trap sunlight with only one or two massive chloroplasts in each cell, while many other plants – especially liverworts, which they are often confused with – have dozens to do this with.

These same chloroplasts are where they store carbon dioxide, which they require for photosynthesis. Not all plants can do this.

If you’re wondering where do Hornworts grow, you’ll most often find them in places like clay banks, on – not in – soil and rock. Others will land on bark instead.

Scientific NameCeratophyllum demersum
GenusCeratophyllum
Other namesHorned Liverwort, Coontail, Rigid Hornwort
Lighting NeedsModerate
Growth rateFast
Temperature Required60-86 degrees Fahrenheit
pH6.0 – 7.5
KH5 – 15
Care LevelEasy
Minimum tank size15 gallons
Maximum plant size10 feet

About Hornwort

Since Hornwort is specifically known for its rapid growth rates, one of the first questions you may have about this plant is “How fast does Hornwort grow?”

It can adapt to almost any water conditions, including a wide range of temperatures, pH, CO2 levels, et cetera.

This actually makes it an extremely great plant for unheated shrimp tanks, since those little critters can be pretty sensitive to many of the parameters Hornwort doesn’t care about.

Hornwort leaves are rather fine but hard in texture, so that makes them difficult for fish and other critters to eat them. And these plants typically have many steps within a single plant which actually created multiple other plants.

Hornwort lacks true roots and naturally floats instead. It can be planted in substrate, however, but it will probably start losing its bottom leaves if it is.

It’s a flowering plant, as well, with both male and female flowers that it uses to reproduce. Each plant has both, which makes it a monoecious plant. The flowers aren’t very colorful, though, and pretty short. The flower produces a single nut with three spines.

The plant produces needles in whorls of six to twelve, which range between lighter green and dark green shades, depending on the environment.

About the Types of Hornwort

There are hundreds of species of Hornwort worldwide, so the term is a bit vague when speaking generally.

However, you will pretty much find that your aquarium keeping varieties are limited to Ceratophyllum demersum when you go looking to buy the plants from aquarium shops, pet stores, and other places.

common newt swimming amongst hornwort

Uses and Benefits of Hornwort in an Aquarium

Hornwort aquatic plant is a versatile plant with its stunning, feather-like leaves and vivid green shades. It is, of course, first most thought of as a decorative plant – which they most certainly are – but they add so much more value to your goldfish aquarium than just pretty looks.

So what are the Hornwort aquarium benefits?

Hornwort is fast-growing, so it can actually help to keep the water values in the aquarium stable. How? Because it gobbles up nitrates, making it a great buffer. It’s especially great for housing with fragile shrimp species that are sensitive to nitrates.

Either a fixed or Hornwort floating plant is possible. Floating is closest to its natural habitat life – and can therefore be a light dimmer for other plants and animals who need less light than some of their tank mates.

Hornwort is also a great hiding place for various shrimp and fish species. It’s especially great for community tanks for helping baby fish survive the maturing stages.

Young shrimp can also hide between the fine leaves and feed on the infusoria until they’re large enough to handle themselves out in the open.

Herbivorous fish – like goldfish – find this plant too difficult to eat, thanks to the hard leaves. But, even if they manage to nosh away some of the needles, the plant is super fast-growing, so they restore quickly.

This gorgeous plant also adds some serious aesthetic qualities, of course. It sways in any current you’ve got going in there, as well as adding some bright color and textures to the fish tank overall.

Hornwort, like other aquatic plants, also aerate the fish tank water by producing oxygen through photosynthesis and using up carbon dioxide produced by fish.

It can also inhibit algae growth and improve the overall water quality in the aquarium through eliminating waste and nitrogen compounds – meaning it works as a natural filtration system for your tank.

Tank Requirements for Hornwort

Honestly, Hornwort care is pretty easy. These plants don’t need a lot of special water parameters or care instructions, which is a big part of why they’re so popular with both newbies and long-time hobbyists.

Water Parameters

Hornwort water parameters are pretty easy going, which makes them very versatile for a variety of tank types. They require temperatures somewhere between 60 and 85-degrees Fahrenheit, which is a pretty broad area of temperature.

In fact, it means the plants can be kept in anything from cold water tanks to tropical freshwater tanks.

They also have a broad pH requirement between 6.0 and 7.5, meaning, again, they’re good with almost any kind of tank. They also do great in both soft and hard water with KH up to 15.

Tank Size

For the best growth and health of your Hornwort, you need to grow these plants in fifteen-gallon tanks or larger.

Because of their fast growth rates, this minimum size is critical. Anything smaller, and you’ll be out of space too quickly to properly prepare more space in another tank or pond.

Fertilizer and CO2

Another thing that makes tropical Hornwort so easy to care for is that it doesn’t need CO2 injection or fertilizer dosing on a regular basis. It can appreciate both, of course, resulting in faster and fuller growth, but it’s not necessary for healthy plants.

Lighting

Hornwort naturally inhabits lakes and ponds and marshes, and since it’s a natural floater, so it needs more light than some of the super easy to care for plants like Anubias that like living in the shadows.

Hornwort needs medium or mid-light ranges to stay healthy and happy. It does also need clear water for proper photosynthesis.

Basic Care for Hornwort

There’s no exact growth rate for this speedy floating plant. The variables that help or detract from growth are too variable, but just to put things into perspective, it’s uncommon for Hornwort to grow more than 5-inches in a single week.

Because of that crazy growth rate, you’ve got some care ahead of you, though it’s still pretty limited to some far more advanced aquatic plants like Cabomba furcate.

The rate of growth you want will greatly impact how you care for the plant. You’ve got to keep basic water parameters in place – see above for the incredibly wide ranges on this – and enough light, but not too much light, et cetera.

Here’s what I mean.

If you want your plant to grow at a moderate, more manageable rate, you do basically nothing except plant it and provide it with mid-level light.

If, however, you want the plant to grow like a weed, then you will want to give it warmer water, brighter lights – but not too bright! – and add in some CO2 injections and fertilizing dosing to your aquarium care schedule. This will result in both more plant and brighter, lighter colors in your plant’s fluffy leaves.

Of course, these “extra growth” options will also affect the rest of your tank, so keep that in mind.

great diving beetle amongst hornwort

Maintenance for Hornwort

To keep your Hornwort healthy, there’s not much you need to do, though you will need to do some trimming at times, especially during heavy growth periods.

The rapid growth rate can easily mean that it quickly becomes too large for its aquarium and will dominate the tank.

This is, of course, not good for your fish, shrimp, or other invertebrates, let alone the plant.

You may find you need to adjust the lighting, CO2 levels, nutrient levels, pH, et cetera over time to gain a fuller control of the growth rates of your Hornwort. The place where this becomes a challenge, however, is the way it affects the other life in your aquarium.

Because of this challenge, it’s recommended that beginner aquarists start with just keeping the plant alive and thriving, rather than propagating and spreading as much.

So, keep the lights on the lower side of mid-lighting, skip the CO2 injections, and avoid adding in nutrient-rich fertilizer unless you notice some of the issues listed below.

For the easiest maintenance, we highly recommend getting some LED lighting system in place.

These lights give you the greatest level of control on brightness, color, warmth, et cetera, which can all be critical to the health of your plants.

Common Problems with Hornwort Plants

Hornwort is an incredibly easy to grow plant. So easy, in fact, that in some countries of the world, it’s considered an invasive species. That means you pretty much don’t have to do anything to keep it healthy.

There are some issues, though, that crop up, because, well, plants are plants and humans are human. Things happen, things change, and some things get missed or go unnoticed for just a little too long.

Overgrowth in the Aquarium

Thanks to the famous rapid growth of the plant, one of the most common issues with growing Hornwort is the domination it may make over the rest of the aquarium.

Its size makes it ideal for large aquariums and ponds – rather than small tanks, though it can be kept in aquariums down to 15-gallons in size – in mid-light environments.

This is an especially challenging problem for the rest of the aquarium rather than the plant, admittedly.

You see, when the plant dominates the fish tank, it prevents other plants and the fish inside from getting light because the Hornwort is covering the water surface. This will kill any grounds plants and will stunt the health and growth of your fish and other critters down there.

To regulate this issue, you need to regularly maintain the plant by cutting the stems and dividing the plants. (We’ll talk more about trimming below.)

Hornwort Turning Brown

Quite often, any plant turning brown is the result of either too much light or transplant melt.

This means you should trim off the dead leaves – a few at a time, not all at once – and let nature take its course. It usually resolved itself within a few weeks.

If you notice, however, that the plant is doing poorly still after some time, test the water nutrients and temperature to make sure things are neither too hot nor too nutrient-poor.

Adjust temperatures or dose some fertilizer to improve these situations.

Needle Shedding

Another common complaint of Hornwort is the volume of shed needles. It doesn’t happen in all cases – some don’t shed much at all – and isn’t necessarily too critical, but it can indicate some imbalance in the tank or the plant itself.

If you notice your Hornwort is shedding its needles at an alarming rate, it’s potentially due to water changes to the aquarium setup.

Whether the plant is new to the tank and adjusting, or other plants or fish have been introduced and water parameters have changed, this challenge isn’t a death sentence for your Hornwort by a long shot.

When this does happen, you generally just need to let the plant adjust to the changes in the environment.

If, however, you notice that the shedding doesn’t stop after a reasonable period of adjustment, you need to look at the water temperature. It may have gotten too high for your plant. If it’s safe to do so, try lowering the temperature.

If that doesn’t seem to be it, test the nutrient levels in the water. If they’re not normal, you may need to dose for a little while to get things adjusted properly.

How to Plant Hornwort

Before we discuss the actual process of planting your Hornwort, we should address the question: Should you plant or float your Hornwort?

Hornwort can be anchored in substrate or it can float on the water’s surface. So, which is better?

The reality is, either/or. It all depends on the aesthetic you’re looking for, the type of fish you keep, et cetera. Either way, your fish will have some great shelter among the needles of the Hornwort.

But surface-dwelling fish – like hatchetfish – will appreciate a floating Hornwort while mid to lower-level swimmers – like loaches and tetras – will prefer planted Hornwort.

Your primary concern should be which will work best for the rest of your aquarium life.

Whichever choice you make, however, be sure to avoid planting it too close to a filter inlet which could be blocked by the plant debris or floating leaves.

To plant your Hornwort, follow these simple steps.

  1. Choose the Hornwort and bring it home.
  2. Place a length or bunch of the Hornwort into the freshwater aquarium.
  3. If you wish to plant your Hornwort, tie some fishing line loosely to one end of the length or bunch and position it in the tank where you’d like the plant to grow.
  4. Anchor the fishing line down with some rocks or other “heavy” enough décor to keep the line in place.
  5. Be sure not to heavily cover the plant base, however, as sinking it too well will cause root rot, which then can poison your aquarium.

Yes. It’s that easy.

How to Trim Hornwort

Trimming your Hornwort is pretty simple, especially if you’ve chosen to go with the floating route.

Many folks actually just reach in, grab a stem, and simply pinch off the plant at the point where you want to trim it.

You can also pinch off side shoots if the Hornwort is branching out too widely for your aquarium’s space.

How to Propagate Hornwort

Propagation for your Hornwort is equally as easy as growing it. You simply pinch off the plant from the point where you’d like to regrow from. It’s really, genuinely that simple.

You just now have to place the trimmings where you’d like to grow more Hornwort, and you’ve started the process of expanding your oxygenating Hornwort jungle.

It should only take a few weeks to see the side shoot or trimming start to grow into a plant of its own.

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