You'll want to remove the eggs from the tank.....or set up a breeding tank just for the clownfish, and remove mom and dad just before the eggs hatch.
You'll also need to culture rotifers...for the first week the fry hatch....and brine shrimp after that.
We had a local club member who raised clowns until he got to the point of too many clownfish and no one to give them to.