Hi Tim
Not sure where you are, but one other choice is a fish normally sold
as a tropical aquarium fish, White Clouds, or aka Mountain Minnows
(Tanicthys albonubes). They actually prefer a cooler water, and as
long as you don't dip out of the 60's in the winter, they do great.
They also reproduce like crazy. They would probably overwinter better
if they did have a deeper area I guess. But they do appreciate a
moving water stream, I've keep them in bucket ponds on my patio in
Arizona, and most did survive winter. The temp of the water did get
into the high 50's in the winter.
I just think they're prettier then plain minnows (OK everyone don't
kill me!)