Ancient Chinese written 3,000 years ago on bamboo describes birds being good for ponds. Birds normally roost over water and their droppings fall into the water. Speculatively, because birds eat mainly cellulose, the microflora of birds has cellulose digesters. These are natural pond bacteria.
The pond bird ecosystem is extremely complex and requires habitat for diverse bird populations. Until this can be established, you will require bird houses and bird feeders including nectar stations. Universally, birds love seeds including millet and sunflower; so plant some next to the pond. In addition because many seed producers make nectar, insects such as bees are attracted. Select locally grown wildflower seed to plant in the winter. Put straw packets in trees and shrubs for native bee nests. The insects provide the invertebrate population for the pond fish, birds and you froggie with a grand diet.
That takes care of birds and bees and flowers, and now trees. Trees as previously mentioned provide shade. Trees provide roosts for the birds. In addition many trees provide nectar and fruit. As importantly, many trees can provide fruit for you. So consider cherry, apple, pear and nut trees.
The most fearsome fish predators for a pond are the great blue heron, eagle and osprey. They often visit every day taking one or two fish. You do not want to kill these beautiful birds but haze them. Song birds such as the red winged blackbird and sparrows win battles defending their pond. A hummingbird protecting a current bush will poke the eye out of anything coming near. If you provide bird habitat, you will not have heavy fish predation.
You see froggie, every plant and animal phyla are present in a pond. If you just dig a hole add water and some fish, you will miss owning a pond. Ponds exert their influence for miles around and if properly constructed will improve the health of the eco-system of which we are all a part.
PonDoc from the pond