If you have two tomato clowns and one hasn't killed the other, then you will have a pair. It often takes a year or so for the female to mature to the point where they will spawn.
It also depends on the circumstances. They need to be well-fed, meaning that she has a bit of a belly. My ocellaris seem to want a quiet cave where they can go at it. They spawned like clockwork every few weeks in their cave in the old 20. Since moving to the new digs, the male has cleaned the same spot for 6 months, but no eggs so far.
Those of us who just hit "new posts" see the thread, no matter where it shows up. I may move this over to propagation if I feel energetic.