Thanks for all the suggestions guys :)
Yes I think I will treat the water before adding any fish. Yes you are correct Ray, we will probably be setting this up right in the middle of summer, so will have to be careful. I was thinking about getting some wakin goldfish (since I can't have my Koi), but I might start with a couple of standard comets from the local pet store before I go buying a more expensive goldfish. I would love nothing more than to go and buy 60 fish and put them all in.... but I know I shouldn't!!
The pond will get little to no shade, so I am definitely going to have