He got a pit before (and flashed) when I had him in another new tank. I was not messing with the filter because I had put in media from another tank. Wanted BB to grow.
He flashed a bit and I saw a pit. I cleaned the filter (vacuum & rinse bio balls), did water change/ media clean and dosed salt. He recovered quickly. Also fed vitamins and garlic. But at that time he was eating. A lot.
Currently he's stressed. I'm not surprised that he may be getting attacked by Hex. His immune system is compromised.
I keep my tanks pretty clean/ frequent water changes (vacuum sump also) and am fairly religious on feeding vitamins to the fish and good pellet and stick food. Theo is the only exception but she got some vitamins yesterday. I have never seen white poop in my tanks. I take pride on taking care of both tanks.
I'm not sure what the root problem with Luther is. Have only seen the flashing. But I gotta do something. This is the first step. We shall see if he eats. That is #1.