Dominant behavior

Hello,
I purchased a pair of tomato clowns a little over a month ago. Roughly the same size, one was clearly dominating the other and establishing the role of the dominant female. Just over the last day or so, it seems hat the roles have been reversed. The less dominant fish is now the aggresor. He has forced the other fish into the corner of the tank and won't let it leave. Is this typical that the dominant role would suddenly be changed, or should I be worried that the once dominant fish is getting sick and weak? Thank you.

 

Its possible that before the dominant one was only taking the role of dominant male. Maybe the other one has now taken the dominant female role and overruled him. Clowns are really hit and miss they may get along again and they may not hard to say.