thanks , temperature at the moment is around 20 [breeding season] in the middle of summer it can get up to 26 max winter low as 10 [Celsius]
the trick is having a big pond which holds the heat better though the nights and diet is extremely important and they should be feed according to temperature and breed.
my mates and i dug this one out took 2 weeks and it's around 8000 Litres. all up cost $1121 exactly [ i was quit proud of my self to do it on budget] that includes pond lining, pump, filter, UV-C light, pipes and clips, sand and river stone.
photo taken a little while ago it has a lot more plants now.