Bob, I'd only throw in LMB as a VERY LAST resort. I'd stock some HSB first. GSF can reproduce @ 2" body length, and they will eat a LOT of the smaller YOY fish. If you only have a small amount of fish in there, I'd consider nuking the pond. Easier to do now then after 1-3 years when you will lose that fish growth if you decide to start all over.