The Kuo-Sho ("Fallen Shoal") is what the Quor-Toa of the Lagoons of Piety call themselves. They struck out from the Barren Sea into Khyber, in search of a safer life. Their former home has conditioned them to live as a collective shoal, and they are entirely communal. They live in one of the larger pools of the central lagoons, where they cultivate the fish and reeds to sustain themselves.
Even in Khyber, they maintain their connection to Dal Quor, and when they were threatened by the Dukedom of Reeds and Water Lilies they manifested a Quori to save them, who was then transformed by the Lagoons into a true god: Vosh. Vosh was destroyed by the Dukedom's own god.
It is a curious coincidence that a people capable of manifesting their own gods would find their ways to a demiplane where everyone can do so.