Freshwater habitats are always the matter of interest for environmentalist and students. In the first half of this book covers the detail account of freshwater habitats like lentic and lontic, ephemeral, permanent, semi-permanent, lakes, glacial, riverine etc. Also, biotic and abiotic feature of aquatic environment, biological complexes associated with freshwater habitats, Ecological zone and classification of animals according to their habitats, Special locomotary and planktonic adaptations of freshwater animals, life cycles stages are discussed in detail. Later half of this book covers the economics of freshwater habitats which includes Biomass, Productivity, The trophic level, Flow of energy, Efficiency of production, Energy transformation in secondary productions, Attribute and development for population, Natality and mortality, Physiological and ecological longevity, Dispersal, Growth of the population, Population density, Distribution of population individuals, Importance of diversity, Purification of water, Stream purification, and Purity of water. This book is of great importance for the life-science students dealing with the freshwater zoology course.