So the tank is a 75 gallon, with 2 clowns, 2 blue dartfish, 1 rainford, 1 purple firefish, and 1 anthias.
When this all started, I had the above fish plus 5 firefish, and a female anthias. They all slowly started getting lethargic, scratching, etc. Some of the fish were breathing a bit hard and coughing. Also some were thin. There was some signs of stringy poop so I started with feeding metro/focus/kanamycin to try and knock out everything. By the time I added prazipro, the fish were dropping like flies, and the last purple firefish was really breathing hard. Its right gill was visibly red and sticking out, and it was going up to the sand and just scratching its gill. After 1st round of prazipro, the fish started spazing the hell out bc of the flukes, but then started to get better, less scratching. No more dying. The purple firefish's gill started to get a little better. Ended up doing two more rounds 5 days apart, and the purple firefish's gill looks back to normal. Fish keep swimming fine and eating healthy.
Now one of the dartfish is scratching on the sand again, and its been having swimming fits. Ill add some food in there, and then itll eat a bit and just dart all over the place, against the sand, the walls. Like its crazy, almost acting like its been stung or something. Its been more lethargic lately. Ive also seen the firefish and anthias starting to scratch again. I dont think its anything aside from flukes because the prazipro definitely helps, it just doesnt seem to knock them all out.