This book supplements the first volume of the Atlas des Poissons d'Eau Douce de Guyane published in 1996. It is intended for naturalists, researchers, teachers, fishermen, managers or aquarists. Its objective is also to be a tool for the managers in order to contribute to the conservation of aquatic communities. Various approaches are proposed to contribute to the identification of the species: keys (more than 500 drawings), descriptive cards for each species, vernacular names of each ethnic. The cards inform about biology, ecology, and distribution, using more than 200 original photographs or drawings and as many detailed maps. This volumes deals with Batrachoidiformes, Mugiliformes, Beloniformes, Cyprinodontiformes, Synbrachiformes, Perciformes, Pleuonectiformes, and Tetraodontiformes in fascicle 1, and Siluriformes in fascicle 2.