@Suzanne C Hi Suzanne: Thanks for your reply. Do you have fish in your pond. Because if you do, the goldfish will be eating the tadpole eggs. The fish will also eat mosquito larvae. I'll just stick with my lovely frogs. I have ensured that they can always get out (because frogs can drown if there is no way out of even a shallow water dish) with some mesh/netting that they can climb out. Even now in autumn, they are still croaking away. I must be doing something right in the garden to have frogs. They are an indication that all is well in your garden. Best wishes.