There are no photos from the actual sighting. The photos shown here were provided from the ALA website, ala.org.au, with the recommendation of Anna van Dugteren from Environment and Planning, ACT Government.
Your right David it has yet to be recorded in the Canberra Region, but it is one that is predicted as being capable of establishing here . It is a plant that we would like people to keep an eye out for and report any infestations before they become firmly established.
Re aquatic ferns, there are two species of Azolla (pinnata and filiculoides) in Lake BG (usually the eastern end due to the prevailing wind) and Marsilea mutica was recorded by Max Gray on a farm dam, though I've not yet found it. See http://www.home.aone.net.au/~byzantium/ferns/descriptions/azolla/azpinnata.html my old, neglected ferns website.