According to this book, Clarkiis "will attack other anemonefishes and passive tankmates." Sebaes are listed only as a nickname for Clarkii in this book, but are indeed a seperate species (A. Sebae).
As for Maroons (P. Biaculeatus) "should never be housed with other anemonefishes or small, peaceful fish species." and Tomatoes (A. Frenatus) "prove to be very belligerent when it begins to mature, striking out at peaceful tankmates, especially other anemonefishes."
Though I believe I have seen A. Frenatus referred to as the Fire Clown, and A. Ephippium as the Tomato, so A. Ephippium is "an aggressive fish that will punish other anemonefishes and smaller, more passive tankmates."
However, as I'm sure you know, there are plenty of people in this community alone who have had very different experiences with clowns of any variety.