What drainage is your pond located on in Virginia? A more suitable option for a Virginia pond over either of the topminnow species is the banded killifish. Very similar species in many ways, except banded killifish are native to Virginia and you can find them commercially available on a limited basis. I have found them to handle predation reasonably well when they have shallow areas with aquatic vegetation to take cover in.
I've got banded killfish on my list of minnows to explore, along with the redbelly dace. I just wasn't sure enough about them to include them definitively in any list. The killfish certainly looks like an option to look at. The only native topminnow I found in Virginia was the lined topminnow.
http://cnre.vt.edu/efish/families/linetopm.htmlHere is a list of all native and introduced flora and fauna in virginia:
http://www.dgif.virginia.gov/wildlife/virginianativenaturalizedspecies.pdfRegarding drainage, the farm is right by the Pedlar River, which drains into the James River.
