Physa acuta? I posted these pics on a facebook snail group and got a reply from John Stanisic (the "Snail Whisperer and author of Australian Land Snails. Volume 1 and 2). Actually the reply was from his wife who says that John identifies the snail as Physa acuta. For some further info see https://www.mdfrc.org.au/bugguide/display.asp?type=5&class=21&subclass=&Order=57&family=216&couplet=0 https://idtools.org/id/mollusc/factsheet.php?name=Physella%20acuta https://bie.ala.org.au/species/urn:lsid:biodiversity.org.au:afd.taxon:3095beba-7e1e-4238-8426-79b8e4173a32 The snail in my photo doesn't show the mottling much but I believe its because the shell has dried in the hot sun immediately prior to taking the photo and also because of dirt and slime from the very dirty pool it was living in.