Author: Efren Leonida
Common Names: River buttercup
Native Distribution: Australia
Aquarium Placement: Midground/foreground
Requirements: CO2 addition recommended
Australia is a relatively untapped source of flora that can be used in the foreground and midground of aquariums. Ranunculus inundatus is a creeping plant that has made its way to North American hobbyists in the past several years from its natural habitat in southeastern Australia.
One of the few Ranunculus species that may grow submersed, R. inundatus has a striking leaf pattern contributing to its rising popularity in the aquarium hobby. Unlike many stem plants, where leaf color changes with variable conditions, the leaves of this plant remain light green in coloration. These properties add to its usefulness as a point of contrast in an aquarium layout. This plant’s rhizome—a central stalk from which new leaves emerge—grows along the substrate. Each structure has one star-shaped leaf that develops on a stem.
Ranunculus inundatus does require medium to high lighting to flourish in an aquarium. Low lighting levels lead to inhibited growth and taller leaves with long stems. As always, higher lighting levels also require steady macronutrient and micronutrient levels from regular supplementation, as well as carbon dioxide addition. Otherwise this plant appears to be undemanding, adapting to a wide range of water hardness and pH values.
Other than its lighting needs, Ranunculus inundatus is a relatively undemanding plant. Often there is an adaptation period when it is first introduced to a tank’s conditions. This may last anywhere from a couple of weeks to a month, where little new growth is seen, although the plants remain healthy.
R. inundatus can be used in an aquascape as either a midground or foreground plant, and is an excellent choice if used as an accent or focal-point arrangement. If lower lighting levels are used, this plant should be used in the midground so the taller stems can be hidden with hardscape or foreground plants. If used in the foreground, high lighting levels promote shorter leaf height, helping to maintain the sense of scale in a layout.
Often, after the initial adaptation period, growth can be rapid. Prudent trimming of stray runners, and the occasional thinning of a grouping by gently teasing a runner out of the substrate and trimming helps maintain a grouping’s shape and effect in the layout.
With patience and adequate lighting, R. inundatus propagates by sending runners from the rhizome, creating new leaf structures as it spreads. These new rhizomes can be trimmed and replanted to make new, autonomous plants.