Several clumps on wet muds and moist organic soils in amongst boulders around a non-flowing backwater, One phot shows he plant underwater (very shallow) and bubbles forming on frond, from photosynthesis.
Interesting, Riccia fluitans is listed on some Australian websites as being for sale in Australia as part of the aquarium plant trade. Could an aquarium discard potentially lead to the establishment of this species in Australia?