"The striped mittenfish, a deepwater species recently discovered in the Java Sea, can change its sex at will by turning its entire body inside out"
I believe that this is a myth, because I have found no other place that tells about it. So no, I don't think there is such a thing, but if there were, it would have a nickname of Bruce and Mr., or is it Ms., Jenner would keep one as a pet.
OK, I have nothing more to say on this subject. Now, you all try and have a great day, you hear?