[Two Clarias gariepinus catfish caught near Bogor, West Java in Indonesia. Image by W.A. Djatmiko via Wikimedia Commons and CC-BY-SA-3.0] There’s one in every school. These aggressive individuals go around pushing and biting their neighbors, goading them into risky behaviors–like breathing. Several species of catfish, including the African sharptooth catfish (Clarias gariepinus), have both gills that take …