Hi Hi Wombat !
well its a good start and in a smaller pond its easy to cull and grow on and get a faster result !plus you should have some good tempratures in Oz ! better than my welsh weather !lol ! .but I see your having bad weather as well with all those floods !.
do you feed clay at all as this is good to bring out colours and patterns just like mud ponds ! I use Boiled barley and clay paste with added crushed silkworm this works well and gets a good skin luster and hi and sumi and shiroji .
this is also a good conditioning food before spawning koi .