Will feeder goldfish breed in a pond?

I just recently bought a stock tank that i'm going to turn into a self sustaining pond. I am heavily planting the pond with anacharis. I'm going to buy 30 rosy red minnows or comet goldfish and the stock tank is 150 gallons (58X38X25). This "SELF SUSTAINING" Pond is a spring break project so their is no heater or filter (plants will act as filter, sun is the heater). I will not touch the pond unless it really is getting dirty so will the goldfish breed? and also, i'm adding a turtle in their, that is why i wanna know if they will breed so that if they do, the turtle can eat the anacharis and fish as his food. i will throw pellets for all the fish and turtles occasionally. are their any other fish that are cheap but will breed?