Neritina variegata - Variegated Nerite

These snails are about 20mm in size and occur in shallow freshwater pools in the streams of the wet tropics (Cairns region). This population of Vaerigated Nerites was quite near (maybe 500m upstream) to the tidally influenced lower part of the waterway. I have only ever seen decollate specimens. They look very dark on first sight but in the right light the spots and variegation show up. Not seen in the video but they have a dark operculum.