How the clownfish earned its stripes

White patterns develop thanks to hormones and anemone friends.

Two clown fish in an anemone. Yhe fish are orange, with white and black stripes. The anemone is made og finger-like brown hairs.
Amphiprion percula, a species of clownfish photographed in Kimbe Bay, Papua New Guinea. Credit: Tane Sinclair-Taylor.