Did you get a full body shot or a good head shot?

Would be interesting to see what the fish looked like on the outside. I would have bet it looked like a hen.

Most critters are pre-programmed to be female on the outside by default. When that Y-chromosome kicks in during sexual development in the embyonic stage, the critter eventually takes on male characteristics. A developmental failure at that point would render a genetically male critter to become female. The biologic explanation for the disparity between external features and gonads is either deficient testosterone production or relative testosterone resistance at the tissue level.

This happens in humans as well... a condition called testicular feminization. Kid grows up totally female, and when they become teens, they look quite girly.... all female parts on the outside... just kinda small in the boobs hips and butts department. First clue that there is a problem is they NEVER get a period. Usually a very devastating revelation for all the family.