The book, Electrophysiology and Fish Behavior embraces 19 chapters having two main parts, namely, electrophysiology and fish behavior. In the first part, the history and behavior of electric fishes were traced out together with the application of electricity for catching fishes. The response of fishes in an electric field and the physiological mechanisms and electrical principles involved in it were correlated thereafter. The empirical studies on the reactions of cold water fishes, warm water Indian and marine fishes and the hybrids in different forms of electrical field (DC, AC, Pulsed DC, Rectangular and Square wave form) by various investigators have been described in details along with the physical, chemical, biological and environmental factors responsible for the intensity of such reactions. The effect of electrical stimulation on the heart beat and body muscle of fish were determined and recorded in the book together with the harmful effect of electric exposure on fertilized and developing eggs, hatchlings, juveniles, older fishes and the man who handles the electric current during investigation and research in the laboratory and field. In the second part of the book, role of olfaction in fish behavior, especially for feeding, stimuli associated with danger, reproductive cues and social interaction been highlighted. Fish behavior in aquarium (in captivity) and in the wild describing their adaptation in different ecosystems were documented in the relevant chapters of the book. Diversity of fishes in different ecosystems and their cooperative behavior with special stress on learning and memory were given in the book. In the last chapter, examples were putforth for applied fish behaviors. The book will be useful for the students, teachers and researchers working on this line.