The Hylasa were a humanoid species native to fluidic space. The Hylasa use the Gekli as means of transport, influencing their movement when bonded, and as a result the Hylasa were responsible to protect them from harm, especially newborn Gekli who are not yet bonded and mostly defenseless.
The Federation and the Klingon Defense Force made first contact with the Hylasa in 2409. Their leader gave the Federation/KDF vital information about fluidic space, when a Federation/KDF ship tried to make peace with the Undine. The leader also helped the Federation/KDF to find a quantum singularity back to their own dimension. (STO mission: "Fluid Dynamics")