Certain fish change sex for certain reasons. Sometimes it's because there are no fish of the opposite sex (clownfish and groupers). Sometimes (I believe, I'd have to look into it more), it's an age thing where they do develop to the opposite sex after a certain ageI was talking to a gentleman I had met cuz he approached me because I had Vic on a leash up at the Brew shop and he was talking to me and I told him kind of what you know what we thought might be going on and his response was that that's not surprising because he studies fish and said that in fish that happens quite often, the changing of gender so to speak. So yeah there's a lot out there that we don't know. A lot of people do not consider the fact that there are answers to questions that we have not yet thought to ask.