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. It can easily grow up to 5 feet tall in the wild. 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. 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 has a wide range of climates. It can be found on all continents, except Antarctica. It prefers to grow in slow-moving, still bodies of freshwater that have lots of organic nutrition in the water column.

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. With enough light and nutrients, hornwort can easily grow 1-4 inches (3-10 cm) per week.

Are snails allowed to eat hornworts? Aquarium snails, also called detritivores, eat only dead leaves and organic debris. A pest snail may be eating plants. This is usually a sign that the snail has removed some of the unhealthy leaves.

Are goldfish allowed to eat hornwort? Most plant-eating creatures (e.g. turtles, koi or African cichlids) don’t eat it. It could be because of its hard texture or slightly serrated leaves.

Hornwort leaves can be a little rough, but they are not perfectly smooth. They have small bumps which give it a slight spiky texture.

How to Care for Hornwort

This aquatic plant can survive at temperatures up to 85degF (or 50-85degF for indoors). Hornwort thrives as a floating species, because it has better access to light. 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 starts to grow out of control, make sure you trim it back so it doesn’t block the sunlight or limit gas exchange.

Hornwort prefers gentle flow so ensure that the needles are not accidentally absorbed by your filter intake. It can grow under low-to-high light and does NOT require carbon dioxide injection. Because it grows so quickly, it’s best to use it as a background plant in larger tanks (unless you have the time to constantly trim it). Due to its rapid growth, it can quickly deplete your aquarium of nutrients. You may have to add Easy Green liquid fertilizer regularly to ensure that all plants are getting enough.

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, 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. You don’t have to throw the whole plant away. Wait for it time to recover, and it will soon start growing new shoots. You should also gravel vacuum the fallen leaves to stop excess nutrients buildup in your aquarium.

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

How to Propagate Hornwort

Hornwort can produce tiny buds in nature. They will fall to the ground when it is cold and spring up when the weather gets warmer. Home propagation involves removing a small portion of the side shoots or trimming the top of tall stems. You can let any hornwort fragment float on the water surface or place it in the soil to grow. It is possible to obtain hornwort by asking around to find out if other hobbyists have 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.