This book, Wallis and Futuna Freshwater Fish and Crustaceans, valorises 10 years of inventories and stu­dies carried out throughout the archipelago. There are about 37 species, 18 of crustaceans and 19 of fish. Among them, 17 species of crustaceans and 17 of fish are present in Futuna ; three species of crustaceans and four of fish are present in Wallis. Finally, four are endemic to Futuna and two species are introduced in Wallis. The reader will find in this book the main characteristics of the archipelago’s aquatic ecosystems. The list of the species, their adaptations to insular systems and the problems linked to their management and conservation will also be developed. In order to determine the diffe­rent species, detailed identification keys are given, as are the main characteristics concerning their description, bio­logy and distribution. Numerous photos and maps are also presented and complete the information given for each species. This book is intended for environment management units, teachers and researchers. Its aim is to serve as a tool to improve knowledge on aquatic environments and on the species inhabiting them, in order to implement conservation and management measures. It has been written in two different languages, French and English.