What Do Elodea Eat?

Water plants, like open-air plants, grow by a process called photosynthesis. They take in nitrogen and give off oxygen. American elodea is a widespread water weed native to North America. Water weeds imported from Brazil, also called elodea, look similar to the native species but are invasive in ponds and lakes in the U.S. and Canada. Both North American and Brazilian varieties are widely used in aquariums.

  1. Quick Identification

    • Brazilian elodea and hydrilla are larger and bushier and have longer leaves than the north American elodea. The Brazilian varieties have four to six leaves in each whorl around the stem. The American water weed has three leaves for each whorl; its leaves are narrower than those on the Brazilian variety.

    American Elodea

    • Elodea Canadensis, the American elodea, lives underwater. Its small, white flowers, attached to the plant by delicate stalks, bloom at the surface. In the fall, its leafy stalks detach and float away to root, starting new plants. Its winter buds spend the winter on the bottom of a lake. In mild climates, it is an evergreen.

      The American elodea especially likes silts and water rich in nutrients, although it will grow in many kinds of sediments. It will grow in shallow to deep water. It can continue to grow floating, without roots. It is an important part of lake ecosystems in many states. Ducks, muskrat and beaver eat it. It is attractive and easy to maintain in an aquarium.

    Brazilian Elodea

    • Egeria densa, the Brazilian elodea, is commonly sold as anacharis, an oxygen plant good for aquariums. It was originally imported from Brazil free of disease and insects. It has no natural predators so when people dumped the contents of their aquariums into local ponds, it spreads quickly. Once introduced, Brazilian elodea forms unsightly mats, choking out native plants and interfering with fishing, boating and water skiing.

      Brazilian elodea plants imported to the U.S. are all male. They produce no seeds. The plant spreads by fragments, sprouting from double nodes about 1/8 inch apart along the stems.

      Aquatic herbices are not effective in controlling Brazilian elodea. Grass carp will eat it, but stocking grass carp is not compatible in ponds and lakes containing runs of salmon and steelhead or lakes needed as habitat for waterfowl.

    Another Brazilian Waterweed

    • A second invasive Brazilian elodea imported to North America is the hydrilla, Hydrilla verticillata, which is similar in appearance to Egeria densa.

    Prohibitions

    • Although Brazilian elodea is sometime sold to aquarium owners on the internet, those buying it should know that it is considered a serious invasive plant.

      Texas has a penalty of $200 to $2,000 or a jail term of not less than 180 days for possessing or selling Brazilian elodea. Minnesota prohibits transporting it, carrying it by boat, or transporting water infected with it. There are laws against selling and owning Brazilian elodea in Alabama, Washington, and Oregon.