In both animals and plants, cells produce new cells by mitosis - but they split differently. A cleavage farrow forms in the animal cell and it splits. For the plant cell, a cell plate forms and then the cell splits.
Fish will eat tadpoles if they can get to them. The only way to stop them would be to give the tadpoles a space that the fish can't get to, like a shallow area with a barrier (plastic mesh would work but make sure the fish can't get caught in it) or lots of plants, or make a separate wildlife pond.
