ThanksThis looks like a form of bloat but sorry I have no idea how to help. I have never experienced this, but have seen a couple of posts on here where people have had a similar issue.
It seems that it has stop thickenning this week. I ask the guy at my LFS (speciality in stingray), he said that usually it caused by internal bacteria/parasite and I started treat it with prazi gold 2 days ago, we’ll see how it goes. He is still active and eat really well. But i reduce the amount of food he eats.I had a hystrix develop a bloating issue some years ago. She stopped eating and eventually passed. Not sure how to help your ray. Has he continued to thicken?