Flame angel pairs????

[iceemn360]

I was just curious.... I've read that some individuals have succesfully kept paris and even schools of these fish with one male and one or several females. First off... HOW in the world can you tell wether they are male or female!!!??? Because they are can change genders (I think usually from female to male) that would normally make the males larger,... right? Also. i've heardd that males have a more pointed tip on the end of their dorsal fin and that it is more vibrantly blue. I searched on google images to see if I could tell anything and so far no luck. Has any one here ever kept a pair or more? Does anyone here know how to sex them???? just another of my curiosities