bird or fish

I'm reading a book about the history of airships at the moment. It starts with a quote by Dr Hugo Eckener - the first expert airship pilot and proponent of the development and use of Zepplins for passenger transport and war machines. Zepplins were invented by Count Ferdinand von Zepplin, a somewhat mad enthusiast who spent years (and lots of money) trying to get the airship idea off the ground.

Anyway Eckener said:

The mass of the mighty airship hull, which seemed matched by its lightness and grace, and whose beauty of form was modulated by delicate shades of colour, never failed to make a strong impression on people's minds. It was not, as genarally described, a "silver bird soaring in majestic flight," but rather a fabulous silver fish, floating quietly in the ocean of air, and captivating the eye just like a fantastic, exotic fish seen in an aquarium. And this fairy-like apparation, which seemed to melt into the silvery blue background of the sky, when it appeared far away, lighted by the sun, seemed to be coming from another world and to be returning there like a dream...