Potential issues
- Algae / weeds in the small, shallow above ground ponds - if you run a pipe and dump water from them into the big in ground pond.

- Birds and four legged predators picking off forage fish from the small shallow ponds.

- Water / air temperature - too hot in Summer and too cold in Winter



Don't know how small you're looking at, but have you considered livestock tanks for minnow raising?

http://www.bettymills.com/shop/super_cat...Commercial.html


http://www.fleetfarm.com/detail/freeland-374-gal-corrugated-stock-tank/0000000033256