My cory along with the others tolerates the 1 Tbl/5 gal of salt rule absolutely fine and has for some time. He's so active it's tiring! LOLchickadee said:The platys and guppies MIGHT be able to tolerate a small amount but the cories will not tolerate even a little bit as they are scaleless fish. No catfish, sharks, or other scaleless fish should ever have salt added to their water. It will kill them or at the very least make them very ill.