Thank you for your response, I appreciate your help.Sometimes, a definitive diagnosis isn't possible remotely, and sometimes, not even in person.
Skip the herbtana, it is just a herbal tonic. Mixing medication with focus and feeding it to your fish also won’t work unless you calculate the dose properly (see the two files on medicated foods at the top of this section).
Based on the few clues I can see in the pictures, I’d say the fish could have flukes. The freshwater dips mentioned will buy you some time, but only one species, Neobenedenia, is large enough to be seen without a microscope in the dip water.
I think you should consider treating the tank with Prazipro, 2x a week apart. Add extra aeration, and run your skimmer, but with no cup.
Jay