cadbury 's freddo frogs have decreased from 15g to 12g .
the recommended retail price of the iconic aussie treat will stay the same .
comes after cadbury shrunk its family size block by 9 per cent .
last year nestle sliced its killer pythons in half from 47g to 24g .
the size of the size of smarties ` fun size ' boxes also shrunk by 20 per cent .