This concise review focuses on recent advances in the function and mechanism of electroreceptive systems in lower aquatic vertebrates and elucidates the sophisticated principles of communication, prey detection and orientation in these organisms. An introduction into electroreceptors, electric organs and sensory functions is followed by a review of electrocommunication and its behavioral physiology. Throughout each section, one finds a wide range of examples, from sharks, rays and skates to catfishes and stargazers, including also strongly and weakly electric fishes from tropical freshwater bodies.