Here's the reason why I said Rotenone. I know it's only one pond, but that is one pond that I don't want to have a repeat of.

A absentee landowner customer had a pond dug in a damp area of the woods. 1 ac, supposed to be 12' deep. Wanted a SMB/YP/RES pond. Didn't want to stock a lot of fish, so he only OK'd stocking 50% of what I recommended (FHM, Golden Shiners, Yellow Perch and Redear Sunfish) Fast forward 2 years when it was time to stock the SMB, he noticed fish chasing other fish in the shallows. I got called, went there and caught two 14" LMB. I KNOW I didn't stock any LMB, and we couldn't tell if any more were in there so he said kill it and we will start over.

I drained about 50% of the pond, then applied the rotenone. There were 1,000's of GSF, no fatheads, only adult Golden Shiners, only adult YP, only adult RES. There was absolutely no surviving reproduction in the pond at all except for GSF. I figure that there were GSF in the puddle in the woods that they turned into the pond because the woods floods and the ditch nearby has GSF in it.

No other LMB were in the pond, and this state has a 14" minimum size for keeping LMB from public waters. I figure some were caught from a local lake and bucket stocked in there because there was no sign of ANY fish chasing forage fish in shallow water before.

When the pond was dug, the spoils were distributed around the pond so no surface water could run into the pond - it is a groundwater pond.

That's why I say kill all the GSF and then stock.