Hornwort: A Complete Growing Guide

Hornwort scientifically called as Ceratophyllum demersum is an aquatic plant and comes from North America. Hornwort plant is easy to grow and can adapt to different water conditions. Another amazing thing about this plant is it grows very fast and maintaining is also very easy. It is a hardy plant.

This plant is available throughout the world except in Antarctica like all the plants this plant also provide oxygen and this plant is ideal for beginners as well.

In this guide we talk about growing hornwort, it’s maintenance/care, benefits and tank requirements.

Hornwort Overview

Hornwort Overview

Care Required: Easy
Family: Ceratophyllaceae
Growth Rate: Fast
Minimum Tank Size: 15 Gallons
pH: 6.0 – 7.5
Alkalinity Levels: 5 – 15 dGH
Temperature: 59°F – 86°F


As already said hornwort comes from North America and it has spread throughout the world accept Antarctica. This freshwater aquatic plant can adapt to different water conditions and this helps hornwort to be grown in a closed tank.

They are found in lakes, ponds, sea as well as other damp and humid places. They also grow on the trees in the tropical rainforest where the regions are little cooler. Though hornwort is a tropical plant it can also survive in water.

There is a disadvantage of hornwort due to its invasive nature Which means it can grow quickly anywhere and can cause to outnumber the native plants in that region and this is not a good thing as we want the nature to be balanced.


Hornwort is a stem plant and its stem can grow up to 10 feet and if the growth is not controlled it can reach the top of the water surface. It has many side shoots and hence it looks bushy. Each shoot consists of tiny needle like leaves and this gives an awesome look and is quite different from the rest of the aquatic plants. The leaves are produced in a spiral pattern and each leaf can grow between 8 – 40mm in length.

It is a monoecious plant, which means this plant has both male and female flowers in it. Usually from July to September the flowering starts, the flowers are small around 2mm and have brown petals. After some time, it produces a fruit which is around 4mm along with three spines with it. Out of the three spines, one is the apical spine and the other two spines are basal spines.

During this season, the buds are developed and the buds fall into the bottom of the water which becomes a new plant and this is the reason of the hornwort to spread and grow quickly.

Hornworts are usually dark green in color, however, they can exhibit light green color if the water is little warm.


There are many benefits with Hornwort, like any plant this plant also gives that aesthetic looks in the aquarium.

  • It photosynthesizes, which means it absorbs light and produces oxygen, so it provides oxygen to other living aquatic creature in the fish tank.
  • Hornwort absorbs harmful chemicals in the water such as Nitrates, carbon dioxide, ammonia as well as phosphate. These chemicals are very harmful for the creatures inside the tank and most of these chemicals come from fish waste and bad water within the tank.
  • This plant also helps in limiting the blue-green algae growth in the tank. These algae can grow quickly and can go out of control if there is too much light and more waste in the water.
  • Like most of the plants, this plant also helps in providing shelter to the fishes and helps the fishes during spawning, so that the newly hatched fry can hide in the plants from big predators.
  • It also helps small shrimps to hide in the plant from other big fishes.
  • Since it grows quickly, your aquarium will be filled with hornwort in no time and this provides a dense look in the aquarium. Though this is a little disadvantage on the other side as pruning required will be more.
  • Sometimes they shed small leaves and these small leaves arefood for few scavenging fishes.

Tank Requirement

In the wild, this plant grows in different kinds of environment like marshes, pond and lakes, So there is no exact way to grow them in the tank and this is a good thing because it can grow in any condition as along as the water the tank is healthy.

Since it grows quickly, it is advised to have a minimum 15 to 20 gallon tank. You can also place hornwort in small tank, however more pruning of hornwort is required in small tank or else it will grow quickly in small tanks and occupy the whole tank and it becomes difficult for other creatures to move easily. Hence it is advised to have a bigger tank.

  • The water temperature required is from 15°C to 30°C (59-86°F)
  • pH required is around 6.0 to 7.5
  • Water hardness should be around 5-15 dGH.

Another important thing is it requires moderate to high light for proper growth using photosynthesis. Also make sure to not use too much light as it can significantly affect other creatures in the tank.

Hornworts can grow quickly, roughly around 2.5cm per week. So regular pruning is required.

Another tip would be let few hornet plants to float on the surface, so this helps in moderating the light evenly in the tank.

If you are keeping any filters, make sure the plants are not near the filter as the inlet of the filter might suck the plants and causes the plants to die and clog the inlet as well.

Hornets can grow on any substrate however, it is advised to have a soft gravel/sand substrate for it to stay and allow few hornets to float as well.

Also have regular water cycle changes, this ensures proper environment for both plants as well as aquatic creatures in the tank.

When it comes to replacing water, it is not a good idea to replace the whole water in the tank as it is going to certainly affect all the plants and aquatic creatures inside the tank.

This is due to a sudden change in the water conditions like different water pH level, different water hardness and also you will be losing all the good nutrients which was there in the water.

Hence it is advised to change only round 25% of the water every week, so that there won’t be too much change in water and the plants and aquatic creatures can live without having any kind of problems. Just ensure that the water added newly has the same temperature, same pH and hardness of the water in the tank.

Also, when cleaning the tank ensure that you don’t use any kind of harmful chemicals or harmful soaps for washing marine ornaments or even the tank glass as this will also affect the creatures and the plants.


Maintaining hornwort is easy, since it grows at a faster rate the only thing required is proper pruning. The rate of growth depends on there is conditions, however it is common for this plant to grow round 5 inches in a week.

If proper conditions are met, this plant can grow at a pretty good rate. This is actually a disadvantage because it requires more pruning. Light and warmer tank also affects the growth.

When to comes to supplements for hornet, you can add little CO2, since this plant is known to consume most of the nutrients, it is better to supplement the tank regularly and another thing to remember here is don’t add too much supplement as it will cause the natural nutrients in the soil to deplete. If you have other plants along with hornwort then adding supplements every week his advised.

Once the plant has grown big enough, it needs to be cut along the stem to the regular size. This process needs to be repeated every time when the plant starts out growing.

Common problems

Few problems with hornwort are growth rate. As already discussed, it starts to grow very quickly and will occupy the whole aquarium if no pruning is done. Due to this it becomes very difficult for other fish is to move inside the tank.

Another problem is if the floating hornwort is if not regulated, it will start out growing and starts covering the whole top water surface thereby blocking the light completely and this will cause poor lighting conditions for creatures or even other hornwort which is grown as a standing plant. This is not a good thing. Hence it is advised to regularly watch and trim the floating plant.

Another common problem is shredding, this plant shreds it’s tiny leaves and you might need to regularly take them off. Usually this shredding happens when the plant is newly introduced into the aquarium or if the water condition is bad. The shredding should stop after some time and when water conditions are proper.

If you see the leaves of hornwort becoming light Gray or black, then it is sure that the plant is either not getting enough light or proper nutrients. It can be also you too bad water. Hence keep in mind be above things.


Growing this plant is very easy. Since this plant is invasive in nature and can grow via vegetative fragmentation where part of the plant gets separated and the new part start going on its own. Usually the part of the stem gets detached.

In order to grow more hornwort plants in the aquarium, you can just cut the side stem and place this newly cut stem on to the substrate or leave it as a floating plant. This new plant starts growing in couple of weeks.

Hornwort Other Plants and Tank Mates

There are no hard and fast rule for hornwort Compatibility, you can add any kind of fish along with hornwort. Usually guppies and mollies like this plant as they can lay their eggs on the leaves which provides a kind of protection for those small eggs for other predators.

However, few plant eating fishes like Gouramis and Angelfish can eat this plant. You need to decide and judge after some time as to whether keep this plant with Gouramis and Angelfish. A properly fed fish usually won’t touch the plants.

You can also keep snails and shrimps with this plant. Also, few scavenging fish like loaches will eat the left-over shredded plant and keep the aquarium clean.


Why hornworts are so called?

They get name due to their horn-shaped spore capsules.

How to plant hornwort?

You can plant it on a soft sand/gravel substrate or can leave it to float.

Can hornwort grow in gravel?

Yes, it can grow on gravel, however they don’t have roots, so you need to submerge the hornet a little till it can stand on its own.

Can hornwort grow floating?

Yes, they can grow even while floating.

Can hornwort grow in low light?

Yes, it can grow in low light, however there will be less rate of growth. It needs medium to high light for proper growth.

Will turtles eat hornwort?

No, turtles won’t eat it.

Will hornwort kill other plants?

No, they won’t harm or kill any other plants, however you need to prune regularly so that it doesn’t occupy the whole aquarium thereby providing space for other plants as well for growth.

What eats hornwort?

Few plant eating fishes like Gouramis and Angelfish will eat this plant.

Why is hornwort so important?

Because it is easy to maintain, It absorbs harmful chemicals. Please see the hornwort benefits above.

Hornwort aquarium Size?

It is advised to have a miniumn 15- 20 gallon tank.


Hornwort is a great plant for your aquarium due to its amazing looks. Ease of maintenance. We suggest you get this plant in your aquarium. This plant is easily available all over the world and getting one shouldn’t be a problem.