I recently had a flowerhorn with the same exact symptoms. I was sure he was going to die. He would not eat anything. I tried the Epson salt treatment using a syringe and feeding tube from my vet. It did not work. All it did was stress the fish. I was sure he was going to die from the stress alone.
I was able to get some pure metro tablets from a local fish farm supply here in the Tampa area. I crushed the tablets and added a very small amount to some water and NLS pellets. I force fed this solution once a day for four or five days. Around day six, he started eating again, but would not eat NLS. I fed him freeze-dried krill soaked in epson salt solution, for about five more days. I also fed him super worms that were gut loaded with metro flakes. My next step was to not feed him for a few days. By then, he was very hungry and went back to eating NLS. I fed epson salt soaked NLS for a couple days.
It's now been a few months and he is doing great. I only feed him NLS. He's gained back all his lost size / kock and has since grown about two inches. The other day I saw him poop out some white stringy pearls, so back on epson salt soaked NLS he went.
I was able to get some pure metro tablets from a local fish farm supply here in the Tampa area. I crushed the tablets and added a very small amount to some water and NLS pellets. I force fed this solution once a day for four or five days. Around day six, he started eating again, but would not eat NLS. I fed him freeze-dried krill soaked in epson salt solution, for about five more days. I also fed him super worms that were gut loaded with metro flakes. My next step was to not feed him for a few days. By then, he was very hungry and went back to eating NLS. I fed epson salt soaked NLS for a couple days.
It's now been a few months and he is doing great. I only feed him NLS. He's gained back all his lost size / kock and has since grown about two inches. The other day I saw him poop out some white stringy pearls, so back on epson salt soaked NLS he went.