ABSTRACT
A great number of animal species are distributed throughout inland waters. The various phyla or classes make up different proportions of the inland aquatic fauna.
Many species of the freshwater fauna originated from land animals. Over time, passive and active invasions occurred from land and sea systems into inland aquatic systems. The present chapter describes the dynamics and interactions of the aquatic fauna, including the structure and functioning of food chains, seasonal cycles, migration (horizontal, vertical and latitudinal), and distribution. The composition and abundance of the fauna and the use of aquatic animals as indicators of water pollution are also discussed.
