Starting on about page 3 of my forage pond thread are a bunch of pictures of RES and hybrids RES/GSF. No guarantee all of them are identified correctly, but I think at least many are.
https://forums.pondboss.com/ubbthreads.php?ubb=showflat&Number=370619&page=3I had bought RES and FHM to stock this pond (fish route truck), and I got a bunch of GSF genes mixed in. It was only supposed to have only FHM and RES in that pond, nothing else as I was raising them to breed and then supplemental stock my other ponds.
I fought GSF genes in that particular pond for a few years.