I am going to suggest you get the High Range pH Test as it is more sensitive than the wide range pH. The wide range pH is really not much good except to tell us which of the other two pH kits we need. And the KH is the one test that I relied on most, unless there was an issue, as a good high KH will provide a stable pH which is needed for both fish and filter bacteria, and if the filter bacteria are happy, the ammonia and nitrite are generally going to be zero.
I don't see any obvious wounds or infections, but you might try antibiotics in the event it is a swim bladder infection. I have never had one, and don't remember anyone successfully treating swim bladder issues. Propping the fish up with blocks won't help, and will most likely cause scratches that can become infected due to the rough texture.
Zone 7 A/B
Keep your words sweet. You never know when you may have to eat them.
Richard