Waterweeds (Elodea) – Care, Growth, Propagation, Light

The Elodea plant is traded under many names, including Anacharis, Elodea densa, and Brazilian waterweed. It is popular in aquariums because it discourages algal growth by absorbing a lot of nutrients. It is a favorite among aquarists who maintain low tech community aquariums, and it is known to be adaptable to a range of aquatic conditions.

The plant can become extremely invasive in the wild, and it needs to be well-controlled by aquarists. Waterweeds have been known to clog up waterways because of the lack of natural predators. Some regions have banned the plant for its invasive potential, and it is best to look up on local regulations before buying it.

Waterweeds Origin

The Elodea plant is indigenous to South America, and it has been recorded in Uruguay and Brazil. The aquarium trade has made it an invasive species in many regions of the world, and it has become established in North America, New Zealand, Northern Europe, Australia, and Japan.

This aquatic plant remains submerged in the water at night and in cooler temperatures, and it floats on the surface to soak up the sun. It inhabits lakes and ponds and slow-moving waterways like canals and streams. The plant thrives in waters up to 4 meters deep.

Waterweeds Appearance

The Elodea plant features an elongated green stem and small green leaves that sprout out of its entire length. Wild plants can have stems of up to 3 ft long and 3mm thick. The leaves grow from the nodes on the stem, and each node will typically have a whorl of 3-6 leaves. The leaves can take on an oblong or oval shape.

There is a cluster of leaves at the tip of each branch. The plant roots at the bottom and you can see the stringy white roots at the base of the stem. The male and female flowers sprout from separate plants, although most Elodea plants sold in pet stores are of the male variety.

When buying an Elodea plant, look out for sturdy green stems and numerous rich-green leaf blades. Most plants will have 6-15 stems which typically range between 6-8 inches in length at pet stores. Avoid plants with limp stems or decaying leaves. The stems can come with roots, or you can buy them without as they will soon grow a new set.

Waterweeds Water & Light Requirements

The Elodea plant is adaptable to various water conditions and it is easy to care for.

The first thing to do after buying the plant is to remove the rubber band at the base of the stems. It is commonly sold in bundles that are bound together for aesthetics. The rubber band can lead to stunted growth if left on for too long.

You can plant Elodea in a gravel or sand substrate or leave it floating. If you decide to anchor it in the substrate, push individual stems about two inches deep. The plant can easily float away if it is not firmly planted.

Keep the temperature between 72-78 °F, and use a thermometer to monitor any changes. The ideal PH range for this plant is 6.5-7.5, with the water hardness between 3-8dKH. It thrives in moderate lighting, and it will quickly die if the light is inadequate. Provide at least 2-4 watts per gallon to keep the Elodea plant happy.

You can add substrate and CO2 fertilizer if you run a tropical aquarium.

Waterweeds Maintenance

The Elodea plant is an excellent background plant for aquariums. Stems shoot to the surface and create a forest-like aesthetic as they grow across the surface. Longer stems will start curling down in a dense arch across the top of your aquarium.

Planted Elodea will develop white and fine roots that will branch across the substrate. Other roots can be seen sprouting from the stem, and they will either remain dangled or find their way into the substrate.

Some aquarists leave the plant to float around the aquarium. It will gravitate towards the light, which will mean that you will have to trim it frequently due to a rapid growth rate.

The growth rate of this plant is generally high in ideal conditions. Adding CO2 supplements and plant fertilizers will encourage the plant to proliferate. You will need to keep trimming the stems to discourage Elodea from overcrowding your set up. The dense growth will, however, offer a hiding place for timid fish and shrimp.

Some fish like goldfish like to nibble on the plant as do some tetras, gouramis, and swordtails.

Waterweeds Propagation

The Elodea plant is easy to propagate, and all you need is a healthy stem that is at least 8 inches long and which has numerous leaves. Trim the leaves at the base of the stem and bury it two inches deep into the substrate. It will quickly develop roots and start growing.

The waterweed plant is well-known for its usefulness in the aquariums. It provides a safe habitat for several small aquatic creatures including fish.

The plant is also a source of vital nutrients for many aquatic animals. Besides fish, geese, swans, and ducks are also attracted to Elodea. It is a reliable and excellent oxygen provider in addition to protecting fry against predators.

Even though the plant is widely accepted among aquarium hobbyists world over, it also comes with its own share of problems. The waterweed plant is known to reduce oxygen concentrations and water temperature in the tank.

This has been always the case especially in summer when the plant dies in its habitat.

Also, its dense growth can cause more problems such as obstructing the light from reaching the tank bottom. This problem can affect most aquarium bottom dwellers and some aquatic plants that depend on light to survive.

Its dense growth can as well create a nuisance with its closed, compact structure becoming a major problem in a given fish habitat. Regardless of its downside, Elodea is still a popular aquatic plant used by many hobbyists in different parts of the world.


The waterweed plant will provide a dense cover for fry, fish, and invertebrates. It is a quick grower if the right conditions are met, and it will filter your aquarium by trapping debris. You can leave the plant floating or anchor it in the substrate.

Aquarium Plants   Updated: May 20, 2020
avatar Hello, my name is Fabian, and I am the Chief Editor at Aquarium Nexus. I have over 20 years of experience in keeping and breeding fish. The aquarium hobby brings me immense joy, and I take great pleasure in sharing my experiences with others.

Leave a Comment

Your email address will not be published. Required fields are marked *