I always have frogs in my pond, bullfrogs and leopard frogs, but never see the tadpoles. My thought is the fish eat the eggs before they get to hatch out. If some do not get eaten, then they are savvy enough to elude the goldies and my eyes by staying hidden. I usually remove the very large bullfrogs to the creek in the pasture~I don't want them eating my fish if I can help it. I did see a toad last year hanging around the pond, probably to lay eggs in there, it was so dry here. This year they could lay eggs anywhere since there seems to be a puddle every few feet!
You are lucky to have fish that let them coexist, my goldies are ruled by their stomachs (that is if they HAVE stomachs!)