fish have white splotches... not ich.. whAT is it

hey i have made a huge mistake. i bought a dogface puffer and a couple days later he seemed sick he had white splotches on his skin his eyes were cloudy and his teeth were constantly exposed.... his skin looked like it was rotting... and he died a few days later... but now my clown grouper, lionfish, and niger trigger have similar aperances.. i am terrified that my fish that i have had forever will face death from a mistake i made of not quarintining this new fish, anyone know what this condition is ? how to treat it? it is not water quality issues