Fish Causing Problem

I bought 3 Bartlett's Anthias at a LFS a few weeks ago. Two of them are small and one is bigger. The bigger one has been aggressive towards all the others in the tank. He is very aggressive towards the other two Anthias. The Tang even hides out in a different spot at night cause the big Anthias took over his spot. Should I sell him because he might be stressing the rest of the tank out? Or will it get better overtime?

 

I think they might be all females not sure how to tell. I read the males have a dark pink spot on their body.. They did all come from the same tank at the LFS and it was small prob 30 gallon. They said they had not been at the store very long. I might just take the big one out and give it away.

 

My tank is 90 gallon

 

I'm going to keep the two small females and got rid of the bigger male. I will sell him for $30 to who wants him. I'm in the Waterloo area