1. Introduction: Environmental Parasitology 2. Parasite - Who I am? 3. Environmental Monitoring – Different Approaches 4. Bio-indicators -Types and their Importance 5. Search for New Biological Sentinels-Do we need Parasite? 6. Parasites-Unique Sentinels 7. Gill Parasites as Biological Sentinels -Evidence from Literature 8. Helminthes as Early Warning Sentinels of Water Quality and Eutrophication 9. Are Parasites Real Contenders for Revealing Environmental Impacts? 10. Parasitism and Environmental Health 11. Environmental parasitology and Ecotoxicology 12. Future Recommendation for Environmental Parasitology