just thought i'd bring this one back from the dead....
my clown started getting black spots as well, and after reading that link, i would say that it is not black ich. it says that 'anemonefish' will get black spots when they come into contact with corals they are not familiar with. i believe that is my case. i have been adding new corals constantly to my tank and the spots are not uniform at all. so it can't be black ich. black ich are tiny tiny black spots that are uniform in size and all over the body.