The study of fishes is called:

Ornithology- study of birds; Herpetology- study of amphibians and reptiles; Ichthyology-study of fishes; Pisciculture- production of fishes.

Ichthyology is a branch of zoology that focuses on the scientific study of fish species, including their biology, anatomy, behavior, ecology, and classification. Researchers in this field, known as ichthyologists, work to understand various aspects of fish life, such as their habitats, evolutionary relationships, and roles in aquatic ecosystems. This knowledge is essential for fish conservation, sustainable fishing practices, and maintaining biodiversity in aquatic environments.