From YT (under video “Last of 11 adult tig catfish, 2015-2022, 3 lost to accidents, 8 to some bug(?), a hurtful experience”):
Brachyplatystoma_juruense: Thank you so much for keeping this video available. Losing an 8-year-old Tig that you cared for over so many years is deeply heartbreaking.
In the past, I also lost one of my own specimens to this exact same tragic progression—a long hunger strike followed by sudden neurological failure and uncontrolled spinning. Thanks to your detailed recording, I was finally able to confirm that my past loss was not a swim bladder issue, but a systemic and neurological failure unique to this genus. It has been immensely helpful and provided real answers for my own fishkeeping journey.
I deeply respect your willingness to share such a painful experience to help keepers like myself learn from it.
Fish-Story: Thank you for that. Since that video I've learned more, actually same year, Nov 2022, I've learned that what had killed our tigs and many other fish was a deficiency of vitamin B1! (Have videos and writeups to prove this beyond any doubt). ... I was NOT supplementing enough their diet of frozen fish, all of which had a varying amount of thiaminase in them. I was not supplementing at all for many years, and after that I was not supplementing enough with VitaChem. These days I supplement enough with VitaChem (presoak thawed fish in VitaChem solution) and add a hearty dose of pure powder of B1 to the soaking solution too. This is the key. 100% sure now. No mystery. No unknown bacteria or parasites or virus. HTH.