Egeria densa care guide

Anacharis or Brazilian waterweed (Egeria densa, Anacharis is an outdated name of the genus, but in the USA and in Canada it is still used) is one of the oldest and the most renowned aquarium plants. Egeria densa is a good plant for beginner aquarists, besides its high growth rate it helps easily settle a biological balance in a new tank.

Habitat in the wild

The habitat is in Argentina, Brazil and Uruguay. Nowadays, the plant has widely spread over Eurasia, North America and Oceania. Egeria densa prefers fresh water basins with lentic or slowly flowing water.

Due to the ability to grow very quickly and tightly fill the waters, Anacharis has got the name of a ‘ditch moss’.

In some areas when the plant gets into the natural bodies of water, it becomes an invasive plant species. When washing tanks it often gets into the open waters, where it quickly forms thick vegetation just of its kind.

Chemical methods are the most efficient ones when getting rid of it. In Brazil, for example, this plant disrupts the work of hydroelectric power stations.

Scientific NameEgeria densa
Common NamesBrazilian waterweed, densa plant
OriginSouth America
PlacementMidground or background
Maximum Size2 m (6.6 ft)
Care LevelEasy
Growth RateHigh
PropagationCut stem and replant
CO2 RequirementNo
Temperature Range72-82 °F
pH Range6.0 – 7.5


Anacharis is a plurannual dioecious aquatic plant. It grows a long stem, which provided with favorable conditions can become up to 2 m long and more. The plant has an upright enrooted stem up to 5 m long and 1-3 mm thick; it is cylindrical, straight or branchy with very short internodes.

The leaves are gathered into verticils from 4 to 8 leaves in each (the bottom leaves are often opposite and there are 3 of them in a verticil). The leaves are linear with serrulate edges 1-4 cm long and 2-5 mm wide.

On the stem there are 4 short lanceolate leaves in each internode (verticil). The distance between the verticils is approximately the same along the whole stem, but it decreases towards the stem end and there is a ‘hat’ made of leaves there.

From the first sight the plant lamina is smooth with flat edges, but if you magnify the image you’ll see that the edges are actually sawtooth ones.

Difficulties in keeping

Egeria densa belongs to the most unpretentiousness and easy in care aquarium plants. The only requirement you should meet is – to provide the tank with the plant with sufficient illumination level.

Otherwise, the bottom leaves of the plant (which usually get less light) may start to rot and fall off.

Simple process of Egeria densa cultivation explains its popularity. The plant can both float near the water surface and stick to the tank bottom.

It can grow almost at any conditions at a wide temperature and hydrochemical parameters range. Though, we should mention that the higher the water temperature is, the lower is the growth rate.

Anacharis actively absorbs saturated organic substances, which is the reason why it grows so actively.

By this the plant suppresses the growth of the latter and enriches the water with oxygen more intensively, than most of other plants. Therefore, this plant can be considered a perfect choice for beginner aquarists.

Care and keeping in a tank

In the 19th century when there were just early days of aquarium hobby and any aquarium equipment allowing to maintain stable water parameters was completely absent, Anacharis was a very popular plant, due to its unpretentiousness.

As a rule you can see the plant in tanks of beginner aquarists. It is true, that in spring and summer provided with bright illumination, Anacharis perfectly grows in a house pond even without rooting, CO2 supply and fertilizers and during the season it fills the whole volume.

By absorbing nitrates the plant sufficiently cleans the water and in doing so it stops unwanted algae from growing in the tank.

Water hardness and pH have no impact on the plant, since Anacharis grows both in very soft and hard water. It is important to avoid abrupt changes of the growing conditions, since this may cause even the plant death.

Anacharis perfectly fits tanks with live-bearing fishes and its thickly growing leaves serve as a perfect shelter for the fish juveniles. In the numerous articles it is mentioned about the poisonous moisture of the plant especially for the fish juveniles, that’s why you should avoid trimming the plant too much in the nursery tanks. As for the adult fishes – Anacharis moisture is not poisonous for them.

Another thing is, that this moisture may have a suppressing impact on growth rate of some delicate aquarium plants. Therefore, when trimming and weeding Anacharis vegetation, you should remove such a sensitive plant from the tank.

The most crucial requirement that should be met for Anacharis to develop in your tank successfully is the illumination level. The lighting should be bright enough and a uniform one.

The plant can easily do without any additional fertilization provided with sufficient amount of organic substances in the tank.

Anacharis propagates rather quickly by means of cutting its stem. If you’ve decided to cultivate the plant, it is desirable that the spring is at least 20 cm long.

After you put it into the substrate, it will strike thin white roots and stick to the bottom using them. You may also leave the sprigs to float in the tank water and, eventually, after reaching the necessary size, they will strike roots themselves.