How pond form?

It begins with the succession of plant life. This is enough to support bacterial life, and attract insects to the pond to lay their eggs and go through the live stage of egg to larvae to pupae then to adult. Fish may be introduced if the pond is large enough or if they are needed to control other animal life that cause complaints to humans. This in turn encourages larger animals like birds and mammals which hunt and eat the fish, insect pupae/larvae or plants that are growing in that pond.