I gave him a 4 day 8-hour Metro bath treatment in a bucket plus forced feeding of medicated bath water each day. It’s very traumatic to him as I nested him out each morning, dumped him into the bucket, and hand held his head tightly while squeezing bath water into his throat with a plastic pipette about 20 times a day. I returned him to the community tank each evening for recovery. It’s more than a week since the treatment. I observed a reduction of white poop , and for the first time in 2 months I saw him pick up couple pellets. His appetite has not fully returned, but he is definitely more active. What is surprising is that, despite fasting for two months, his belly has not caved in, so probably he ate tiny bit without me noticing it. I will wait and see if he shows further improvement before administrating further treatment.
I don’t believe in the need to treat the entire tank. He has been showing symptoms for 2 months, yet none of his tankmates show any symptoms of infection. I believe hex are ubiquitous but opportunistic affecting only stressed out fish.