I have always had trouble growing good eating size and later good numbers of YP with GSF. GSF are very predatory of all types of natural foods including small minnows needed by YP. GSF also eat lots of YP fry up to 1.2" long. YOY GSF seem to be good at avoiding predation from YP. They do not really live in the same areas or niches so they do not interact much,,,, so as a result YP do not eat lots of little GSF. Way too many GSF are able to survive with just YP as predators. I think the GSF will out compete the YP for foods and current YP will remain skinny. It is my experience GSF manage to eat lots of tiny and small YP. Your pond might be big enough and spacious enough for YP to manage to get decent annual recruitment that results in enough YP fry surviving to create a decent YP panfish pond. However I doubt that will happen because the GSF had a very high density head start before you added YP breeders. Now a mostly unknown fact....... GSF have the same mouth size as a LMB until the GSF is around 6" long. After 6" the LMB mouth starts growing more than that of the GSF. I did a GSF mouth size measurement study about this for a Pond Boss conference presentation topic. This means larger GSF of 3"-6" are aggressive and when abundant will eat a huge amount of perch fry until YP are 1.5" to maybe 2" long. GSF at all their body sizes will eat lots of little YP. In my ponds Little GSF 1"-3" decimate perch fry as they hatch from the egg up through swim-up sizes to 3/8" long. Larger GSF eat lots of 1/2"-3/4" YP plus lots of other invertebrate foods needed by small 1"-3" YP. Do you see the problems of your plan? The more GSF there are the worse this problem becomes.

The big unknown that I have is how well will HSB eat GSF. I don't think HSB will eat small GSF very well because GSF live mainly close to shore among rocks and cover and HSB live a lot in open water and will IMO eat many more small 2"-5" YP compared to them eating small GSF. If you add LMB they will eat lots of GSF and YP. When and if the GSF numbers get minimized the LMB will focus on eating YP and eventually keep them from recruiting new YP. The amount of habitat and type of habitat might be a variable in your favor and your goal for producing some decent YP - but I doubt it. When your stocked YP die of old age in several years the YP population will be basically done / gone unless you keep stocking more adult YP. I hope you can prove me wrong. I consider those damn green sunfish pests.

Since you have already twice stocked YP into the pond, your next management objective I think should be to use fish traps, or seining or frequent small bait angling to try and determine if the 2"-4" YP are becoming a noticeable part of the fishery. If yes This means YP are able to recruit YP with the current population structure of GSF in the pond. Whatever happens going forward,, PLEASE return to this thread and tell us how your pond fishery is progressing. We all can learn from your results regardless of the results. We are all here to learn.