[Alexa]

Female groupers change their sex to male if no male is available!

Interesting fact: Female groupers change their sex to male if no male is available!

SOURCES: https://en.wikipedia.org/wiki/Spawn_(biology)#Cuckoldry

^{By Diliff - Own work, CC BY 2.5, https://commons.wikimedia.org/w/index.php?curid=533734}

[MSL]

 To be clear -- it's the biggest fish on the photo.

[Alexa]

Yes, it is. More about this fish: https://en.wikipedia.org/wiki/Grouper .