The famous electric eel (Electrophorus electricus) generates strong electric discharges for prey capture and defense. Other genera of fish have evolved to use electricity to sense objects as well as to communicate between individuals. Weakly electric fish have evolved independently at least two times in evolutionary history and is now present within two groups of fish – the South American knifefishes and the African freshwater elephantfish. The weakly electric fish generate an electric field around their body using a special electric organ. Electroreceptors are distributed over their skin making it possible for the fish to sense perturbations of the self-generated electric field, which translates in to the detection of objects and other fish. In this way, the fish can “see” in turbid waters and even through visually opaque objects. A documentary (“Amazonas elektriska fiskar”) about electric fish (electric eels and and knifefishes) in the Amazon-basin is currently available at SVT-play: