A Delta Quadrant species seen running a narcotics trade from a space station on the edge of the Nekrit Expanse, where Neelix becomes entangled with them in Fair Trade.
The Kolaati appear in the Voyager episode Fair Trade. In 2373 Voyager stops at a trading station at the border of the Nekrit Expanse, a vast region that marks the limit of Neelix's knowledge of the quadrant.
Neelix, afraid he is about to become useless to Janeway, meets an old Talaxian associate, Wixiban, who is in debt to a Kolaati gang led by Tosin. Wixiban draws him into delivering what proves to be narcotics, and a dealer is shot dead with a Starfleet phaser. The Kolaati then demand warp plasma from Voyager as payment.
Neelix confesses to the station manager Bahrat and proposes a trap. At the handover he vents the plasma and dares Tosin to fire, and the gang is arrested. Neelix returns expecting to be put off the ship and instead receives a stern lecture and extra duties.