They have an ear for music

Partly because they’re easily trained, goldfish make for popular test study subjects. In one such study conducted by Keio University, goldfish were taught to distinguish between the music of two classical composers. One group was trained to nibble on a ball of food when they heard pieces by Johann Sebastian Bach.

A second group was taught to do the same but with Igor Stravinsky. When scientists swapped the composers the fish no longer showed interest in eating, suggesting they could tell the difference between the two styles.