Charismatic clownfish, the coral reef fish made famous by the film Finding Nemo, are instantly recognizable by their white stripes. These stripes, which scientists call bars, appear as clownfish mature from larvae into adults in a process called metamorphosis, but how these distinctive patterns form has long remained a mystery.
Now, a new study has found that the speed at which these white bars form depends on the species of sea anemone in which the clownfish live. The scientists also discovered that thyroid hormones, which play a key role in metamorphosis, drive how quickly their stripes appear, through changes in the activity of a gene called duox.
Something else I didn’t know about clownfish is how they transition from male to female over time:
Anemonefish are sequential hermaphrodites, meaning they develop into males first, and when they mature, they become females. If the female anemonefish is removed from the group, such as by death, one of the largest and most dominant males becomes a female. The remaining males move up a rank in the hierarchy.
I’ve got an idea for a Finding Nemo sequel!