Bicolor Anthias

[Xeno]

I was wondering if anyone knew how to identify the sex of these fish. 

One of them has a mis-bar of pink/purple behind its head.  Also a Strip down the front of its face. 
The other is just plain yellow on top pink/purple on the bottom.

I noticed the mis-bar one likes to swim next to the other Anthia I have and smack it with its tail, whats this mean?