Cannot add any expert opinion here but can at least give my experience as it pertains to Grass Carp. Added 30 Grass Carp to my pond 3/acre in 2013 because of Southern Niad. within two years it was wiped out completely. Not sure that's what I wanted but..........I do believe that it has prevented my black crappie from getting out of control based on nowhere to hide. I have owned my pond since 2010 and my water clarity has always been super clear. So far it all works fairly well. I have removed 115 Bass 46 Crappie and 10 Bluegill in 2020. My biggest Bass being 7lbs 11oz. and a 17 1/4" Black Crappie. Just this summer have started seeing a little more vegitation started to come back. Fighting Muskrats now. At least the side benefit of those is they have removed a lot of cattails. Like I said not really sure this helped in the conversation just another perspective.
RER, I noticed the pristine appearance of your water in your photo of that great LMB. I meant to return to that thread and comment on it but it fell so deep in the active posts that I lost track of that. I admired the fish considerably but the backstop of your water and the far hillside really completed the picture.