The building blocks of English

Affixes

ichthyo-

Fish; fishlike.

Greek ikhthus, fish.

Ichthyology is the branch of zoology that deals with fishes; ichthyosis is a congenital skin condition which causes the epidermis to become dry and horny like fish scales; an ichthyosaur is a fossil marine reptile of the Mesozoic era; someone who is ichthyophagous (Greek phagein, eat) eats a lot of fish.