Ceratophyllum demersum (Coon's Tail) is a submerged or floating aquatic perennial with stems that can reach 10 ft (300 cm) and branch at right angles. They bear numerous side shoots making a single specimen appear as a large, bushy mass. The dark green leaves are produced in whorls of 6-12. Each stiff and brittle leaf is simple, or forked into 2-8 thread-like segments edged with spiny teeth. Tiny unisexual flowers with greenish-brown petals are produced in the leaf axils. Coon's Tail is usually found free-floating or loosely anchored in the mud. It is a cosmopolitan aquatic species that can be found in ponds, lakes, ditches, and quiet streams with moderate to high nutrient levels. It spreads both by asexual reproduction of broken or complete stems and by sexual reproduction of very many seeds. Turions or short, densely-leaved resistant stems, develop then break off to float around the water body before they sink to the bottom over winter, where they rest until they re-grow in spring. Coon's Tail is useful as oxygenator in water gardens or aquariums, and as shelter for small fishes and aquatic invertebrates. It has also been introduced deliberately into polluted bodies of water in bioremediation projects because of its ability to absorb suspended particles of chromium, lead, arsenic, and other chemicals.

• Grows up from 6 in. to 10 ft. tall (10-300 cm). 
• Performs best in full sun to full shade in water 12-36 in. deep (30-90 cm).
• A fine choice for water gardens, aquariums.
• No serious pest or disease issues.
• Propagate by stem cuttings and allow to float in water.
• Native to North America.
• Coon's Tail has been spread throughout the world via the aquarium and pond trade, and is considered to be a weed of waterways in many regions of the world, due to its ability to spread rapidly, invade a wide range of aquatic habitats, and grow to deeper depths than some other weed species. 
• Before planting outdoors, gardeners should contact their local department of fish and wildlife for more information on invasive species and noxious weeds.