This book content five chapters comparing to references which focus on biodiversity of ptychobothridean parasite in fishes such as senga and circumoncobothrium. Their identification and adverse effect on host i.e different economical important fishes from Godavari Basin. Biochemical part include estimation of glycogen, protein and lipid. Histopathology shows the pathological condition of host infected due to parasite. Population dynamics shows different seasonal fluctuation of parasites in different month. In all research focus the biodiversity of fish parasite and how they effect their economical and medicinal value due to parasitic infection.