When God made fish and told them to be fruitful and multiply, He gave some of them very special abilities so that they could do this. Some 23 families of fish actually change from females to males, or from males to females, to help their species reproduce.
This ability to change sex, as do tropical fish, produces some amusing behavior. Clownfish are particularly popular among fish hobbyists, who might find that top female fish they recently purchased has become another male! The wrasse family often spawn on large coral reefs, dominated by stronger, territorial males who chase the weaker males away from the reef. But often the smaller males will take on the appearance of a female. Under this disguise, they join the line of females that are waiting to spawn with the dominant male. While in line, these pretenders encourage the ladies in waiting to spawn with them rather than with the large dominant male.
This biological clowning poses a couple of problems for believers in evolution. For one thing, it encourages the very opposite of reproduction of the strongest and best. And there are so many different kinds of fish that change sex that evolutionists have decided that they must have evolved several times.
Of course, we know that the natural ability to change sex came from an imaginative Creator.