Anacharis makes a great beginner aquarium plant. The trickiest part of the plant is probably the name; Anacharis is the old scientific name, replaced by Elodea and now Egeria. However, Anacharis stuck, and it usually sells under this name. It adapts well to captivity, and you can readily propagate it through cuttings.
Anacharis adapts well to a variety of conditions. However, it will grow fastest if you provide ideal conditions. This includes a subtropical temperature between 50 degrees to 70 degrees Fahrenheit, about room temperature. It grows thicker and more robust under these conditions. Additionally, it can survive in low light but will rapidly grow under strong aquarium lighting, around 5 watts per gallon. Anacharis is not particular about substrate, one of the few aquarium plants you can just stick in aquarium gravel and have it thrive.
Wait to cut the plant until it is at least 8 inches long. Then, cut the plant 3 to 4 inches from the top. The original stem will branch off from the cut point. Trim the leaves off the lower half-inch of the new cutting, then carefully push the stem into the substrate. The new cutting will send out roots to anchor itself and begin growing. Additionally, Anacharis will branch on its own. You can cut off the branches once they reach that same 3 inches to 4 inches in length.
Anacharis can reproduce with flowers. However, this is rare in aquariums and seldom seen in ponds. When Anacharis does flower, the topmost part of the stems will send out a short stock that reaches about an inch above the water. The stock grows into a small white flower with three petals. Since this plant is so ridiculously easy to propagate in captivity, letting it flower and growing it from seeds is not considered an efficient means of propagation.
When you keep Anacharis, you need to be careful with the plant. It's never a good idea to release aquarium plants or animals into the wild, but Anacharis has a track record of getting established and choking out native plants all over the world. In some areas, it can grow thick enough to clog waterways. Always dry out or burn Anacharis cuttings, and never flush them down the toilet. In short, never give live Anacharis a way to get into local waterways. Anacharis is so potentially invasive that many regions ban the plant.