I would feed them at the same time that you always feed them. If they are embracing or actively courting, wait to feed them. You will know they are done spawning when there are eggs in the nest and they are no longer embracing.
You will just know when there are eggs, they are little yellow dots that are obvious against the nest. That first embrace probably was a "false" embrace, since usually they will keep embracing in rapid succession. Don't be sorry about questions!