This study was conducted to know the morphological variations between two different strains of Nile Tilapia, Oreochromis niloticus. This aquatic chicken is emerging in a large scale all over the world including Bangladesh. So, farmers need to select the suitable strain which will grow fast and ensure them more profit. This book will chronologically discuss different morphometric and meristic variations between traditional GIFT and recently developed GIFU strains which will help the farmers as well researchers to identify the better one.