Le Carnaval des animaux was conceived in a small Austrian village, while Camille Saint-Saëns was working on his 3rd Symphony with organ, opus 78. Afraid that this humoristic fantasy could cause his oeuvre to be taken less seriously and harm his reputation, he forbade its being published during his lifetime. Aquarium came seventh in the fourteen-number 'Grande Fantaisie zoologique'.

The original version of this piece called for an extensive instrumentation: flute, 'harmonica' [celesta], pianos...