SICK FISH MINUS 1 CLOWN LOACH help!!

[ANGELMINE]

I noticed my severn had white cloudy mess on his fin,so i did water change added some salt ,after few days i added fugus med...2 days later my 3 inch clown loach was dead.....then my electric blue demsy is got white coat and sitting on bottom.my other loach is flashing on bottom.trying to figure out is it fungus,bacterial,parasite??????????????any answers would be helpful..i think the meds kill the loach??