Technicolor Dream Fish: How Tilefish Flash

The chameleon sand tilefish is a unique fish capable of rapidly changing its color, often displaying a spectrum of colors. Found mainly in the Indo-Pacific, this fish is also popular in aquariums. Researchers have discovered that the tilefish's color change is due to iridophores, cells that can adjust the color they reflect. This rapid change is facilitated by the arrangement of platelets within the iridophores, which respond to chemical signals like norepinephrine. While the exact reason for this ability is unknown, it may relate to mating, threat response, or other behaviors.

What chemical is involved in triggering the color changes in tilefish?

What are some possible reasons for why tilefish change colors?