A piscivore is a carnivorous animal that primarily eats fish. The name piscivore is derived from Latin piscis 'fish', and vorō 'to devour'. Piscivore is equivalent to the Greek-derived word ichthyophage, both of which mean "fish eater". Fish were the diet of early tetrapod evolution ; insectivory came next; then in time, the more terrestrially adapted reptiles and synapsids evolved herbivory.

A carnivore, or meat-eater, is an animal or plant whose food and energy requirements derive from the consumption of animal tissues whether through hunting or scavenging.