Be sure and check all your water checks, PH,General hardness(GH) Carbonate hardness(KH) and ammonia. if anything is out of line it is best to adjust before you add the fish, Much easier to adjust, you can adjust far more quickly with no bad effects, and less stress on the fish when you go to add them. Also when adding fish, in that small of a pond just a few and don't spend a bunch on them, This is the time when they are most fragile. Once the pond cycles and establishes itself then finish adding the few really nice fish you want to compliment the pond.
BTW, It looks very nice!