Fenbendazole. When, how and how much?

[flowerpower]

Hi, can anyone break this down for me? I'm using this drug for the first time and want to do it right.
I'm treating a 3-4" flowerhorn that is withering away on me for no apparent reason. I bought the fish only Weeks ago. Seemed healthy in the store but soon after i got him home i realized something was off.
He ate sporadically at first but eventually stopped. Never really settled.
Not eating, listless, loss of weight and color. I have just finished feeding w/ Epsom salt for 5 days w/ no results...
I'm not sure what my paramaters are but all my other fish are thriving.
Thanks in advance for any and all help i can get.

 

[Oddball]

There's no true gauge for using this med. However, I've had success adding 1/8 teaspoon to a capful of Vita-Chem and a few drops of garlic appetite booster. I mixed this into a couple of cubes of thawing bloodworms or beef heart and let it soak for an hour along with a half teaspoon of Focus (binds meds to food).
I fed this process for three days and again for 3 days after 5 days from the first run of treatment.
On the 2nd day of treatment, my fish expelled a dead worm. After that, his appetite improved and I haven't had a problem since that bout.