Just to share, i don add in any medication for my fish when they are sick.
I will just quarrantine the sick fish in a quarrantine tank. Quarrantine tank is 100% conditioned or aged water with salt added. Wont feed the fish for 3-5 days depending on its condition. Continue for couple of weeks to see if there is any recovery of the fish. I find that by using this method, some of the sick fish will recover by its own.