A formicarium or ant farm is a vivarium which is designed primarily for the study of ant colonies and how ants behave and for the enjoyment of ants as pets. Those who study ant behavior are known as myrmecologists.

A vivarium is an area, usually enclosed, for keeping and raising animals or plants for observation or research. Water-based vivaria may have open tops providing they are not connected to other water bodies. An animal enclosure is considered a vivarium only if it provides quality of life through naturalistic components such as ample living space and natural decor that allow and encourage natural behaviours. Often, a portion of the ecosystem for a particular species is simulated on a smaller scale, with controls for environmental conditions such as temperature, humidity and light.