Complex sentence: Upside-down catfish, "Synodontis nigriventris", is a species of catfish, particularly noteworthy for its habit of swimming upside down most of the time.
Split into simpler sentences: Upside-down catfish, "Synodontis nigriventris", is a species of catfish. It's particularly noteworthy because of its habit of swimming upside down most of the time.