Tadpoles

 

probably----Common Eastern Froglet Crinia signifera
These small frogs are only 2 to 3 cm long. They are rarely
seen but are heard in all parts of Sydney. They make a
“creek-creek” noise and occur anywhere where there is very
shallow water and somewhere to hide.

from:  http://www.fats.org.au/Publications_files/FF7%20April%202006.pdf