Hi Claude,
When you are at Lake Herbert, have a look for the Tasmanian Tree Frog
Litoria BurrowsaeThere was a good population at the lake during the 70's / 80's.
They were grey in colour, & a good size, sitting on the rocks at the waters edge & plopping into the lake as you approached .
If you are fishing from the shore at Lake Mackintosh or Lake Rosebery send me a pm
Regards Overlandman
Info on the Tasmanian Tree Frog
http://www.parks.tas.gov.au/index.aspx?base=5227