Edit: I’ve treated 2 times small doses with paragaurd not prazi sorry I mistook the two.
Ok, last post - I'm not going to go any further beyond this. My time here is limited, if you want to save this fish pay attention to the small details.
I have kept several FH over the years, I have authored more than a few stickies on this forum, a couple of them on FH, and one specifically on treating sick FH.
From everything described thus far, IF your fish is sick (it definitely appeared stressed) , it is most likely pointing in the direction of spironucleus, commonly referred to as Hexamita. Or just piss poor water quality, and will improve with improved water quality. Has it? Who knows, this has been like one big guessing game, with little info supplied via the only person that can, which is you. FH don't just suddenly wake up one day with worms - so Prazi most likely won't help at all, and neither will Paraguard (it's designed to killl ectoparasites, as in parasites on the "outside" of your fish)
And neither will salt, aka sodium chloride.
IF your fish is sick, a big IF at this point, the greatest odds from everything posted thus far from you, which ain't much, is pointing in the direction of spironucleus, which many healthy fish carry internally, only to surface when a healthy fishes immune system has been compromised. Piss poor water quality could be enough of a trigger to bring on stringy white feces in a FH. That's typically the first sign of spiro/hex. If that is the case, your fish will soon stop eating so I suggest you speed this up.
Could I use aquarium salt instead of epsom
NO - Not all "salt" is equal. epsom salt = magnesium sulfate
Magnesium sulfate | MgSO4 - PubChem (nih.gov)
Follow the info that I linked to with the epsom salt treatment. (twice now)
If your fish does have spiro/hex, your time to react is limited, so the more time that you waste going in circles the greater the chance that your fish doesn't survive. Don't use any products with surfactants/soaps/fragrances in it. It will kill your fish. Walmart carries pure epsom salt aka magnesium sulfate.
Good luck.