[salt newbie01]

I have been looking at the diff wrasses for some time now and have decided to add a pair of carpenter's flasher wrasses to my goby dominated 58. I hope their peaceful despostion will get along with my gobies - It is an lps dominated tank with mainly acans and micros. It has approx a 2 1/2 inch sand bed and is not jam packed with rock. but there is enough rockwork to give ample hiding places.

My question is how to tell if the 2 wrasses my lfs gets in for me are male or female? If they morph from female to male how can I tell if one or both have changed already? I do not want to get 2 males and have them fight and kill each other. ANy tips you could give would be greatly apreciated.

Thanks in advance