Your Friend Is an Amateur Aquarist Learning to Breed Clownfish

Your friend is an amateur aquarist learning to breed clownfish.She had one successful clutch of eggs,and moved the mother and fry with their anemone to a separate tank leaving only male fish behind.Now,she is surprised to find that a new female fish has appeared in the original tank.What is the most likely explanation for this?

A) Some anemone species secrete pheromones that control the sex of fish as a way to regulate predation.Removal of the anemone allowed a new female to develop.
B) In urban areas,tap water is polluted with contamination from endocrine disruptors such as BPA and PCBs.When she removed some of the tank water for the new tank,she should have replaced it with bottled water.
C) Clownfish are protandrous hermaphrodites that respond to social cues.Removal of the dominant female allowed the second-largest fish to transform into a female.
D) Clownfish synchronize their mating based on seasonal cues indicated by salinity.When she replaced some of the tank water,the lower salinity caused the fish to change into a female.