Ceratophyllum demersum, commonly known as coontail or hornwort, is a submerged, rootless aquatic plant native to lakes, ponds, and slow-moving streams and rivers worldwide. It is typically found in freshwater environments with nutrient-rich conditions. Coontail can grow up to 10 feet in length, forming dense, bushy masses that can be free-floating or anchored in the substrate by modified leaves. The plant has a feathery appearance, with forked leaves that resemble a raccoon’s tail, hence the common name.

Coontail is valued for its role in aquatic ecosystems, providing habitat for fish and invertebrates, oxygenating the water, and helping to control algae growth. It is often used in aquariums and ponds for these benefits. In cultivation, it requires minimal maintenance, thriving in full sun to partial shade conditions, and is tolerant of a wide range of water temperatures and pH levels. However, it can become overly abundant and may need to be managed to prevent it from dominating water bodies.CC BY-SA 4.0