"Tag my Fish" is web and mobile application with a social network concept useful for anglers, ichthyologists, and ecologists. It presents, unites and connects all fish species with all body waters in one place, both in the context of sport fishing and in the context of ecology and protection of waters and aquatic ecosystems. Anglers can upload photos of their catches and tag the fish species, the water on which they made their catch and fishing gear used for the catch. If they tag the fish species incorrectly or simply do not know what they have caught, the system will automatically re-tag the catch and select the correct fish species as soon as possible.