What is causing my fish to flick themselves off plants and ornaments?
“Flashing” or the scratching can be the result of many things: too much salt or medication irritating the fish, toxins irritating the fish, electric current irritating the fish, imbalance of water chemistry and pH, and of course the all too common parasite. You should rule out water chemistry by evaluating the chemicals you put in your tank as well as checking basic water chemistry (pH, nitrates, etc). If you are not adding salt or medications, have high water quality, and no stray current, likely it is parasites. The medication you reference is a fine anti-parasitic medication. It can be a bit harsh, and should be used in a quarantine tank ideally. It is not safe for inverts (pull out any shrimp, snails, etc) and usually isn’t safe for delicate fishes. But it should treat a wide variety of parasites. As always before any medication, improve water quality as much as possible (do a water change).
