I thought, well, what the heck, why not learn about saltwater tropical fish, too? Going slightly in ABC order, I decided to pick out a member of the angelfish family first.
These fish are amazing in that they not only exhibit some intense sexual dimorphism (male and female are colored differently) but they are also Protogynous Hermaphrodites. This term refers to organisms that are born female and at some point in their lifespan change sex to male(Protandrous hermaphrodites are organisms that are born male and at some point in their lifespan change sex to female). But, the Bellus can even change back from male to female, their original sex.
What is the benefit of this behavior?
Protogynous hermaphrodites are most often fish that form harems– one male overseeing numerous females for life. The two main roles of the male are to defend its territory against other males, and to court and fertilize his females. If the male dies, either from natural causes or combat-related injuries, the harem’s dominant female will undergo a sex change from female to male, which can take as little as 5 days. The new male takes over all responsibilities of the previous male until his own passing.