Anacharis, a hardy and easily kept plant, is probably the most commonly kept aquarium plant.
Anacharis, Brazilian Waterweed, and Elodea are all common names used to for this species, Egeria densa. While this species is most suitable for a tropical aquarium, it can also be kept in cooler water. These same common names are also applied to the American or Canadian waterweed species of the Elodea genus, which are very similar. Elodea species are suitable for cool aquariums or ponds however, rather than tropical environments. To be certain of which 'Anacharis' you are obtaining, be sure to check its scientific name.
Anacharis will root if the shoots are buried in the gravel, however they can be kept either as floating plants or as rooted plants. They grow very well in ponds and goldfish tanks and will survive in cold water. They are great beginner plants because they adapt very easily, grow quickly, and are easily propagated. They are also good oxygenators. The stems will grow up to 50 cm (20 in) or more, so they usually need to be kept trimmed.
For more Information on keeping a planted aquarium see:
About Planted Aquariums, Adding Aquatic Plants For a Healthy Aquarium
Anacharis or Brazilian Waterweed Egeria densa originated in South America, in warmer areas of the temperate zone. It can be found in Argentina, Paraguay, Uruguay, and Brazil and has also been introduced into North America, Africa, Europe, and Japan.
Temperature: 50-77° F (10-25° C)
pH: 6.5 - 7.5
dCH: Prefers hard water
Light level: Moderate
Cut stems will readily root in sand or gravel.
Anacharis is readily available.