Zebrafish have become increasingly popular model animals in preclinical and neurobehavioral research due to their genetic similarity to humans and rapid rate of reproduction. Studies of zebrafish behavior have shed light on social and biological phenomena ranging from the dynamics of collective animal behavior, such as shoaling and schooling, to anxiety, fear, and leadership. Borrowing from decades of work on mice and rats, most observations of zebrafish are conducted using a two-dimensional approach, despite the fact that zebrafish swim in three-dimensional (3D) space.