These are some of the first goldfish ever seen in Europe.
The image (which I found in a great Public Domain Review article) came from Histoire naturelle des dorades de la Chine, written in 1780. As the PDR article puts it:
Histoire naturelle des dorades de la Chine (1780) — the dorades in the title refers not to sea bream but the fish’s gilded appearance — was the first monograph on goldfish published in Europe, from a time when the fish were still bound up with Eastern exoticism in the Western imagination. The book begins with a coloured portrait of the benevolent-looking Emperor Quianlong of China, followed by nearly thirty pages of French text by the writer, Louis-Edme Billardon de Sauvigny (1738–1812), introducing the goldfish and giving “observations and anecdotes relating to the customs, customs and government of this empire”.
The book itself has a fascinating history, written shortly before the French Revolution by a king’s courtier who was in communication with two Chinese priests.