John,
I dont know if you remember the issues i had about 4 years ago with my p14. But they got extremely swollen and was breathing very very heavy, and as KNH said they both pulled through and they looked terrible just like your little pup. I talked with Vet's, Biologists, and many other experienced fish experts, and no one could tell me what i should do or what was going on.
I just kept the tank parameters perfect. I suspected possibly gill flukes so i did treat with prazi as well, and dosed according to the bottle and then came back and did it again after a couple weeks. My little ones didn't eat for a couple weeks but finally started coming around and are extremely healthy now.
Now, im not sayin the prazi did anything, and it may have been risky giving to a weak ray but the rays got better.
If it was me, i would isolate to make sure he isnt getting stressed, if you can keep from moving him even better. Maybe a floating nursery?
When i first noticed mine were acting funny they were with some bigger rays and maybe it was all stress related.
If you want i can try to find the thread and the youtube videos of my pups.
