"Black" perculas are actually a melanistic morph of ocellaris clownfish. You can pair black ocellaris with orange ocellaris, since they are the same species. There are also "onyx" perculas, which have much more black on their bodies than "regular" percs, but they still aren't all black.
Some people (most notably Dr. Sanjay Joshi) have also successfully paired and even bred black ocellaris and percula clownfish.