This association includes vegetation with the water fern Salvinia natans, which freely floats on the water surface. It is usually accompanied by lemnid species, and the proportion of cover of Salvinia versus lemnids broadly varies from place to place. In the Czech Republic, it occurs only in mesotrophic to eutrophic fishponds, although historically it has been also recorded in oxbows. It is thermophilous vegetation, which has never been common in the country. Natural occurrences are in the lowlands around Ostrava in north-western Moravia.