I believe somewhere in the Culture series books it is mentioned that many Culture ships also have gas dwellers as inhabitants. By neccesity in separate compartment from the usual terestrial-lineage passengers. I like to believe that alongside all the fractal complexity of Culture life depicted in the books they also have a paralel world with even more exotics. Maybe there is a gas-dweller equivalent of Contact going around Jovians galaxywide getting into all kind of schenanigans.