Planning on getting a pair of clownfish but don't want them to breed?

I'm planning on getting a pair of clownfish once my tank finishes cycling but if I do get a pair, they will breed right? I don't want baby clownfish. What happens when they do have eggs and the babies then hatch and die, wouldn't that crash my tank? Also I was thinking about adding one cardinalfish before adding the clownfish. Should I do that?