D c fish undergoing sex change
Millions of people saw a dramatic example of this in the first episode of Blue Planet II, in which a ten-year-old female kobudai also known as an Asian sheepshead wrasse, Semicossyphus reticulatus changes into a male. After many months, the transformed male emerges from its lair larger than before, bearing testes, a huge bulbous forehead, and an aggressive nature. Now even larger than the existing dominant male it had previously mated with when female, the new male defeats the aged alpha in a violent battle for dominance. The footage is remarkable — but the transformation is actually not terribly unusual. Some like the kobudai change routinely from female to male.