If you can get a few good quality photos, I will try to confirm what species they are...
Emerald ShinerIf they are indeed emerald shiners, there is a slim to none chance they will naturally reproduce in even large ponds. The Maryland DNR tried to introduce them to several small lakes(between 75 and 300 acres) with no success. They would maintain for a few years and then slowly disappear. They truly are a big water species...
There are a number of species that look similar, so once we get some photos we can make a solid ID. However, there are just a handful of shiner species that will do well in ponds.
Golden shiner
spotfin shienr
satinfin shiner
red shiner
spottail shiner
Other than those 5, there are some species than can live in ponds but will not flourish and if they ain't flourishing they ain't making good forage so there is not point in stocking them.
I know Bill has and is playing around with a few other species of shiner to see if he can get them to spawn, but thus far it appears he isn't having any luck. Most shiner species require running water, clean gravel and other specific requirements or all of the above. Few ponds have that...