These environments occur in streams or rivers that flow directly from mountains to the sea and only in high rainfall areas. Stream flows need to be high all year round to prevent saltwater pushing up with the tides. Although in some areas, seawater may creep in below a layer of freshwater. Vegetation on the banks will always feature riparian plants of non-mangrove affinities. Mangroves may be present, particularly species which like brackish water. During extended dry conditions, when freshwater ceases to flow, seawater may fill the entire system, however this penetration fails to create lasting salinity in the channel or on the banks. Waters are usually clear and not the thick blues and browns of of brackish systems in which waters slowly mix.

This list only accepts taxa that are species or lower