How to Care for Hornwort in Aquariums and Ponds
Hornwort is a popular aquatic plant for both fish tanks and outdoor ponds because of its fluffy-looking stems, extremely fast growth, and ability to consume excess nutrients from the water. Learn more about hornwort care and whether it’s right for you.
What is Hornwort?
Ceratophyllum desmersum has many common names such as rigid hornwort (a frequent misspelling), hornwart, and coontail. It grows very tall in the wild and will easily reach all the way to the top of your aquarium or pond. Normally hornwort is found floating at the water surface, but when planted in the substrate, it looks like a fluffy underwater bush with many long branches or side stems. Bright green leaves with a stiff, thin texture are similar to pine needles. Hornwort is similar to water-sprite, javamoss, and has dense foliage which provides excellent protection for shrimp and baby fish.
Where is Hornwort found? Hornwort thrives in all climates, except Antarctica. It prefers to live in water bodies that are still or slow moving and contain lots of organic nutrients.
Does hornwort clean water? Fast-growing plants like hornwort are good at “cleaning” aquarium water because they consume waste compounds from the water (e.g., ammonia, nitrates, and phosphates produced by fish waste and excess fish food) and use it to grow more leaves. With enough light and nutrients, hornwort can easily grow 1-4 inches (3-10 cm) per week.
Does hornwort get eaten by snails? Aquariums snails are called detritivores. They don’t eat living plants but only decaying leaves or other organic material. If you see a pest snail eating a plant, most likely the plant has some unhealthy leaves that the snail is cleaning up for you.
Do goldfish eat hornwort? In general, plant-eating animals (such as goldfish, koi, African cichlids, and turtles) do not eat hornwort. Possible reasons could be the slightly serrated leaves, hard texture, or taste that makes it unpleasant as food.
Hornwort leaves may not be perfectly smooth, but they have tiny bumps that give them a slightly spiky texture.
How to Care For Hornwort
This aquatic plant can live in a huge temperature range from around 50-85degF (10-30degF), so you can put it in tropical aquariums, cold water tanks with no heater, and outdoor ponds (where they can often survive the winter season depending on your climate). Hornwort thrives best when it is a floating plant. It has more light and carbon dioxide from air. It can be planted in the substrate or attached to hardscape by some people. However, it does not grow roots and the attached end will rot away. If your hornwort starts to grow out of control, make sure you trim it back so it doesn’t block the sunlight or limit gas exchange at surface.
Hornwort prefers gentle flow. Make sure your filter intake doesn’t allow the needles to get caught up in your filter. It can grow in low to high light conditions and does not require CO2 injection. It grows quickly so it is best to use it as background plants in larger tanks unless you have time to maintain it. Its rapid growth rate can quickly drain your aquarium’s nutrients. Therefore, you might need to periodically add Easy Green liquid fertilizer to the water column to ensure that other plants have enough food.
Why are my hornwort leaves falling off? Hornwort can shed its needles when there is a significant change in the water parameters, lack of light, and/or if it has been exposed to chemicals such as liquid carbon or strong currents. This is most likely to happen when the plant is new to your tank. Do not throw out the entire plant. Instead, wait for it to recover. It will soon begin to grow new shoots and leaves. To prevent any excess nutrients building up in your aquarium, gravel vacuum the fallen leaves.
Hornwort may be easily propagated simply by cutting off a section and floating in a new tank.
How to Propagate Hornwort
Hornwort can make little buds in the wild. These buds will drop to the ground in the winter and then sprout when it warms up. The most common way to propagate hornwort at home is to trim the stem’s top or cut a side shoot. If you allow hornwort to float on the surface, or if you plant it in the ground, it will quickly grow into a new plant. It is possible to obtain hornwort by asking around and seeing if anyone has any extra trimmings. They are often more than willing to share. We do not sell hornwort because it doesn’t survive in shipping very well, but we have a whole collection of our favorite beginner plants for you to browse.