Problems
Transferring spawn or tadpoles from other ponds runs the risk of spreading diseases, such as red leg disease of frogs, or introducing invasive pond weeds that can quickly choke the pond with vegetation.
To avoid disturbing amphibians, especially in the hibernation period, ponds should not be cleaned out unless this is really necessary.
Have you seen any sick or dead amphibians or other wildlife in your garden? Register and report it on the Garden Wildlife Health website.