Find out how they did the application. Deep water with O2 sometimes acts as a safe haven. If there are carp left then there are others as well (catfish/bullheads, and other poor water quality survivors) but should have taken care of the GShad. They should have taken steps to avoid that. If you think you (the subdivision group) saw most of the dead fish you should have seen the bottom - a lot end up there. Glad for the GShad report and the confirmation of the problem. Any pics of the fish to share ?