Ichthyology is the branch of zoology devoted to the study of fish. This includes the bony fish (Osteichthyes), the cartilaginous fish (Chondrichthyes) such as sharks and rays, and the jawless fish (Agnatha).

Ichthyology has traditionally emphasized the systematics, anatomy, and distribution of fishes.

The practice of ichthyology is closely connected with marine biology, limnology, and oceanography.

On the other closely connected with, physiology, embryology and the nutrition for aquaculture.