one of my FM ( smaller ) has alota green on the top fins ( dunno what that part is called ) while my other FM ( the bigger one ) has no green up on the fins.. can that indicate male and female???
what do you mean by "acts more male"? If you mean aggression-wise females can be worse. As for color, females can be more colorful during breeding. I'm telling you, you can only 100% know for sure that it is a pair if they pair up. Give them time.
I've read that a sure way to sex firemouths is that if the fish turns around clockwise more than counter-clockwise it is for sure a male. If it turns around counter-clockwise more than clockwise it is a female...