I have a 70 tank I have 5 gold barbs, and 4 rosy barbs ome of which is female, they all got on well at first but as of yesterday all the fold barbs have started chasing my female rosy they just keep pestering her I have plenty spaces for her to hide but I am worried they are going to end up killing her. They will chase the other rosy barbs but not nearly as much as they do with the female, what could be causing this?