John - Thanks for providing the pictures. As esshup says positive identification will be best with one out of the water. You will get an education for trying to capture one of these smaller fish. It's harder than it first appears. Try catching one or two in a minnow fish trap baited with bread or broken pieces of pet food. Another option is to use a decent sized fish net with small mesh 1/8", 3/16, or maybe 1/4" for larger ones of 1.5"-2". Lay net in the water and bait it with wet bread or pet food. Lift the net when fish are in the net.
From the overhead picture with fish in the water it is pretty hard to do a correct identification especially when they are smaller. However the fish in your pictures are too bulky on the front half of the fish for them to be yellow perch. YP are slender bodied fish when viewed from above. IMO from what I have seen so far,,, definately not yellow perch.
