No offense but I doubt you received "sick fish" from your supplier, considering 25% (probably more) of the restocked fish have died already. Your pond has a lot of bad variables. In my opinion, you have either high ammonia (bad ammonia NH3) and or low dissolved oxygen. The gills on the bluegill in your photo seem a deeper red, a sign of both.
Stocking your pond so quick never allowed it time to build a favorable ecosystem.
The high water temps are bad for the development of NH3, low DO and in general, the fish.
There is no growth around your pond and no trees for shade. Not good for anything.
Try testing your pond in the early evening to see if you have a rise in pH, nitrates and ammonia. The higher the temp, nitrates and ammonia, the lower your DO and higher your NH3 will be. A temp of 85F, pH above 7.5 and I would guess, high NH3.
You should also autopsy fresh, dead fish.
What should I look for in an autopsy?
