This volume includes six chapters that present updates in animal science and zoology. Chapter One examines the use of zebrafish model system to investigate the pathophysiology of schizophrenia. Chapter Two consolidates facts about melatonin and its involvement in the regulation of fish populations. Chapter Three explores the interaction between the native aquatic gastropod, Valvata humeralis, and invasive aquatic gastropod, Potamopyrgus antipodarum, along a biotic gradient of density in a system where it was suspected that an interaction shift was occurring. Chapter Four explores competition and facilitation between these two gastropods. Chapter Five analyzes the role of superoxide dismutase in reptiles under toxicity contexts. Lastly, Chapter Six analyzes and assesses the corpses of three English Bulldog puppies that had anasarca, a fetal malformation that presents generalized edema.