i want a pair of banggais....
do you know what gender yours is?
sexing could be easy if you know someone with a male.... put it in a tank with the male. if they fight like hell, they are the same ---.
your best bet, if you want a pair, is to buy a few, and see which ones pair up, then return the others to the LFS if they will allow that. But if you want to garentee to keep your own fish, then it owuld be trouble.
some people claim they can tell bangaiis appart without watching their behavior. The jaw of the male is more square for carrying eggs, but this usualy only happens once he has reached sexual maturity. also, the male will have a longer dorsal fin. But fins are often nipped off, or scratched off, and are not always at their full hieght.