Lookin Good mate! Before you start putting fish in it, i reckon it would be wise to get some food growing in there first like firetail gudgeons and shrimps and such, if you have already thats good, but if you havent,,,, go to your local aquarium shop and ask if they could order you some in for cheaper price than normal, some shops may do it some might not, just gotta find a decent one.
Not Sure on how many fish, personally i would put say 30 of each species in depending on how many species i put in, if there were less species i would put more in. I would only put a small amount in cause you have to consider the live food thats in the dam, if you have too much fish in there they could wipe out there food source.
Cam