1 Introduction 2 External Morphological Characters 3 Internal Anatomical Characters 4 Morphometric and Meristic Traits 5 Length-Weight Relationship and Condition Factor 6 Alimentary Canal 7 Food and Feeding Habits 8 Urinogenital System 9 Identification of Maturity Stages in Fishes 10 Estimation of Fecundity in Fishes 11 Determination of Spawning Periodicity by Intra-Ovarian Eggs 12 Age Determination 13 Nervous System 14 Circulatory System 15 Osteology