Two beluga whales who serve as Starfleet navigation specialists in the Cetacean Ops tank of the USS Cerritos, speaking in subtitled whale song and forever inviting crewmates to swim.
Kimolu and Matt are beluga whales holding the rank of lieutenant junior grade aboard the USS Cerritos in Star Trek: Lower Decks. They work in Cetacean Ops, the water-filled navigation section long mentioned in Star Trek but never before shown.
They first appear in First First Contact, the second-season finale. When the ship must be flown through a debris field with its outer hull removed, a crew member has to swim through their tank to reach a vital control, and the pair cheerfully press everyone to get in the water.
They return in Trusted Sources, where Kimolu tells a visiting reporter how much he enjoys the unlimited fish, and are seen again in later seasons.