Gymnotidae is a family of fish commonly known as knifefish, found primarily in freshwater habitats of South America. They are characterized by their elongated bodies and lack of dorsal fins, which gives them a knife-like appearance. These fish are known for their ability to generate electric fields, which they use for navigation, communication, and hunting. Members of the Gymnotidae family are typically nocturnal and can be found in various environments, including rivers, lakes, and swamps. They feed on small invertebrates and other fish, using their electric discharges to locate prey in murky waters.