About the Amazon Frogbit
Species Type: Freshwater Plants
Care Level: Easy. Adaptable, will tolerate soft or moderately hard water, low to medium light, some additional fertilization beneficial or necessary. pH 6.0 to 7.5, GH up to 15 degrees/260ppm.
Origin: Occurs in lakes, ponds and slow-flowing rivers throughout South America.
The round thick waxy leaves grow out from a rosette forming a pod that will then send a runner out from which another pod will develop and successive runners and pods; these can be seen in the second accompanying photo which shows the plant from the below the surface. The underside of the leaf is covered by a thick aerenchymatous cushion that at first glance resembles a cluster of snail eggs.
The plant is very prolific, and will soon cover the surface and should regularly be thinned out. A very attractive surface cover in aquaria, and numerous small characins (pencilfish, tetras) frequently browse the dangling roots. Should not be too close to the light or the leaves may burn.
This plant will also grow emersed as a bog plant in wet sand, and is thus useful in paludaria and terraria.
The Hydrocharitaceae family, commonly known as Frogbit, to which this plant belongs is quite varied; it contains plants as diverse from each other as the subject species, Vallisneria, Egeria, Elodea and others. There is no real similarity between many of these genera.
There are other plants very similar in appearance that may be confused with Limnobium laevigatum. Limnobium spongia is a native North American Frogbit, and Hydrocharis morsus-ranae is a European/Asian plant sometimes referred to as Common or European Frogbit. This latter is a very invasive plant that was intentionally introduced into North America via Ottawa, Canada in 1932. It has since spread quickly and by 2003 was known to occur throughout much of southeastern Ontario, southern Quebec, northern New York and Vermont and eastern Michigan. "Frogbit" is classified in several states including California and Washington as a noxious weed. It is likely that some aquarium plants are in fact not L. laevigatum but one of the other two.
Ideal position in aquarium
Floating surface plant, or emersed as a bog plant in a paludarium or terrarium.
Moderate to bright, usually irrelevant since the plant is on the surface under the light.
Minimum Tank Suggestion
Ideal water parameters for Amazon Frogbit
Soft to moderately hard, acidic to slightly basic/alkaline (pH to 8) water, temperature 18-30C/64-86F.