The Animal life in the pond needs balance also. Plan your animals so that every level of the pond has an animal feeding; my pond has,

frogs

frogs eats flying insects above the pond (store bought)

turtles

turtles eat food at the surface, middle and bottom of the pond (store bought)

Fish

Gold fish eat food at the surface, middle and bottom of the pond (store bought)

Mulisk

Snails eat algea and waste fish food on the surfaces (rode in on store bought elodea)

Zebra Mussels eat algea and plankton suspended in the water (not in my pond yet but sooner or later they be here brought in my ducks, Zebra Mussels came in from Europe in hold water in Ocean going freighters and are a real problem in the Great Lakes, they have no natural enemies here)

worms

Many diferent worms find there way into the pond ( they are brought in by birds, mainly ducks)

tadpoles

tadpoles eat algea and waste food on the bottom of the pond and grow into frogs and toads (most are store bought in my pond, but some are local)

I think it is important to have amphibians like frogs in your pond because, they are in decline in nature for reasons not completely understood. Your frogs will grow and sonner or later escape, helping to repopulate the natural habitats.