Typhlonectidae, also known as aquatic caecilians or rubber eels, are a family of Gymnophiona amphibians found east of the Andes in South America. They are viviparous animals, giving birth to young that possess external gills. Of the five genera in the family, Atretochoana, Potomotyphlus and Typhlonectes are entirely aquatic, while Chthonerpeton and Nectocaecilia are semi-aquatic. Atretochoana reaches 100 cm (39 in) in length, but other species in the family range from 20 to 60 cm (7.9–23.6 in).