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 about the care requirements for hornwort and whether or not it’s the right plant for you.

What is Hornwort?

Ceratophyllum desmersum has many common names such as rigid hornwort (a frequent misspelling), hornwart, and coontail. In the wild, it can grow to a height of approximately 3 feet and can reach the top of any aquarium or pond. Hornwort is normally found floating on the surface of the water, but it can be planted in the substrate to look like an underwater bush with many branches or side stems. The bright green leaves look similar to pine needles. They are rigid and thin, with stiff edges. Much like water sprite and java moss, hornwort has dense foliage that provides excellent protection for baby fish and shrimp.

Where is Hornwort found? Hornwort thrives in all climates, except Antarctica. It prefers to grow in bodies of still or slow-moving fresh water with lots of organic nutrients in it.

How does hornwort clean the water? Hornwort plants are fast-growing and can “clean” aquarium water. They consume waste compounds such as ammonia and nitrates from fish waste and excess fish foods and then use that water to grow more leaves. Hornwort can grow up to 1-4 inches (3-10cm) per week if it has enough nutrients and light.

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.

Can goldfish eat Hornwort? Generally, plant-eating animals like turtles, koi and African cichlids don’t eat Hornwort. It could be because of its hard texture or slightly serrated leaves.

Hornwort leaves are not completely smooth but have small bumps that give it a slightly spiky texture.

How to Care for Hornwort

The aquatic plant can survive in temperatures ranging from 50-85degF (10-30degF) to tropical aquariums. Hornwort grows best as a floating plant, where it has greater access to light and carbon dioxide from the air. Some people like to plant it into the substrate or attach it to hardscape, but because it never grows proper roots, the attached end tends to rot away. If your hornwort grows out of control, you should trim it so that it doesn’t block light from other plants and limit gas exchange at the surface for fish.

Hornwort prefers gentle flow so ensure that the needles are not accidentally sucked up by the filter intake. 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. The most common occurrence is when you first add it to your tank and the plant is not used to your water conditions. Do not throw out the entire plant. Instead, wait for it to recover. It will soon begin to grow new shoots and leaves. Gravel vacuum any fallen leaves to keep excess nutrients from building up inside the aquarium.

Hornwort is easily propagated by trimming off a section and floating it in a new fish tank.

How to Propagate Hornwort

In nature, hornwort may form tiny buds that fall to the ground during cold seasons and then sprout when the temperature warms. A side shoot can be cut or the top of a tall stem can be propagated at home. A single hornwort segment will soon become a new plant, if it is allowed to float on the water surface or planted in the ground. 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, as it isn’t able to survive shipping. However, we have many of our favourite beginner plants available for you to view.