Hornwort (Ceratophyllum demersum) is also known by the more descriptive name, coontail. Hornwort coontail is an herbaceous, free floating aquatic plant. It grows wild in much of North America in calm ponds and lakes and has spread to all other continents except Antarctica. It is a useful cover species for fish and aquatic animals.
What is Hornwort?
Hornwort in ponds protects small frogs and other animals. Fish tank owners may also find hornwort aquarium plants to purchase. While it is a useful as an oxygenator for captive fish, it also grows rapidly and can become a bit of a problem. Hornwort coontail leaves are arranged in delicate whorls, up to 12 per whorl. Each leaf is divided into many segments and feature bendable teeth at the midribs. The stem resembles a raccoon’s tail, hence the name, with a rough feel. It is used in breeding tanks to hide fry and as an aesthetic touch to aquarium displays. Best of all, it oxygenates the water and helps prevent algae. This is because it releases chemicals that kill competing species. This allelopathy is useful to the plant in the wild as well. Hornwort in ponds has similar attributes and can survive temperatures of -2 C in full sun to full shade.