This is a fascinating piece from the i:
Male clownfish – the orange fish … seen in the film Finding Nemo – chnge their sex if their female mate dies, according to new research.
A paper presented at the University of Exeter shows that the fish become female in order to better protect their territory. Female clownfish are more aggressive than their male counterparts, with some even attacking sharks.
Male fish tend to look after the eggs,while their partners scan the area for predators and attack any other fish that encroach. When a male fish’s partner dies, the study found, its gender changes completely to the extent that it will be able to lay eggs.
Dr Mills, co-author of the paper said “The largest individual is the female and if that female gets predated upon or dies, the male – Nemo’s dad – then changes sex and becomes a reproductive female. So when Nemo finally gets back to his anemone at the end of the film, he’s actually meeting his mum.”