Tanis was an Ocampa male. He was a descendant of the Ocampa that Suspiria took with her when she left the Ocampa system in what was the mid 21st century on Earth.

Thanks to Suspiria spending 300 years working with the Ocampa, Tanis had quite advanced mental abilities. He was also 14 years old in 2372 - Ocampa living on their homeworld had never lived past nine years of age. (VOY episode: Cold Fire).