I would have agree that what you are most likely describing is minnows from the Dace family, but as I looked into things I found a few sites describing a Dance minnow family. Now is it just a misunderstanding or a typo on their part, who knows but the ones site I have attached below is from the DNR in Illinois. I would hope they have it correct. Either case interesting learnings here.

Here is a site with southern redbelly Dance minnows :
http://dnr.state.il.us/LANDS/education/fish/minnow.htm

And here is a site with what I am more used to as the Dace family of minnows:
http://www.coordinatedreview.org/PA_Exec/Fish_Boat/pafish/fishhtms/chap11.htm

I didn't think there was a Dace and a Dance minnow but I guess I learned something new today.

---------------------------------
1/10 - 1/4 acre pond plus 16 ft deep/ Plus 40 ft by 20 ft by 6 ft deep koi and fathead minnow pond next to it. Upstate NY