There are three species of redbelly dace. Northern, southern and mountain... The only species that can reproduce in a pond is the northern species. They tend to prefer tannic boggy waters with lots of vegetation. The other two species can survive in ponds, but would not be able to spawn without running water. So, if you want them as a forage species, the northern species is the only option. As far as where to find them... That's the trick! There are a few places on the internet that sell them for aquarium use on occasion. However, they are PRICEY!!! $4-$15 per fish... It would be best to purchase a handful, stock them into a rearing pond, allow them to reproduce and build in numbers and then transfer them to your larger pond with predators in them. If your larger pond doesn't have predators yet, stock the small number of fish and give them a year or two to reproduce. That or collect them from the wild, which carries its own set of risks and challenges...