Egeria Najas


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Aug 10, 2005
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Miami, FL
Scientific name - Egeria najas

Common terms - Slender-leaved elodea, Egeria genus known collectively as Oxygen weed, Anacharis

Geographic origin - South America (Brazil, Argentina), distribution has expanded North. See below.

Type (stem, bulb, rhizome, floating, etc.) - Stem plant in deep tanks, can be used as a floating plant in shallow tanks. I use it as a stem plant.

Max. size (height, width) - Maximum height 80cm, Width 2-3cm (per stem), leaf length 2-4cm, leaf width 2mm.

Lighting required - Low-High, see below. Mine is grown under 3.7WPG

Temperature - 19-27C. Mine is grown in 24C

Water chemistry requirements (pH, hardness) - pH 6.0-7.2, kH 5-15. My pH is 7.0, kH is 9

Growth rates - Fast

Demands - Low, see below.

Additional info - Egeria najas is often confused with Egeria densa, and the two are similar, except the leaves of E. najas show a prominent seration to the leaf edge, whereas the seration in Egeria densa, according to sources, is only viewable under magnification. E. najas also has narrower stems and 5 leaves vs. 4 in densa. E. najas is an undemanding plant that propagates using lateral shoots. Cutting is another form of propagation. E. najas thrives with stronger light, CO2 injection, and the addition of nutrients. It will grow under low-light conditions, but the plant is paler and the stems are much thinner. A distinctive feature of this plant is the sharp downward curve of each leaf. This plant, and others in the Egeria genus was used to oxyginate waters in fish farms throughout the world, and as a result, it has spread well beyond its region of origin. It is on obnoxious weed lists in several State, FL is among them. Egeria najas, is growing in popularity as an alternative to E. densa, and I have found it to be a lovely plant, more resistant to higher temperatures than E. densa. It is also an excellent "algae buster", though I recommend regular trimming.


Sources: Baensh Aquarium Atlas, Volume II (Numerical statistics, and region)
Botanical Electronic News (Noxious weed information)
Practical experience

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