This description of the social and reproductive dynamics of clownfish groups really sounds like something out of kink erotica:

"The small social group of clownfish consists of a single mating pair; a dominant female and small male, as well as several smaller, subordinate non-breeders. Loss of the dominant female results in protandrous sex change of the small male, and maturation of one of the subordinate non-breeders to replace the breeding male."

From: https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/protandry