mine used to do this, first of they were fine, then they did this for a while,few scrapes n battle wounds esp the lip area, and circling round like that, if they run off like that they will need a few hiding places to escape the winner, watch it mind as it could turn nasty, mine are fine now always together, they do lip lock alot/clean rocks alot and chase each other a bit, normal behaviour but always watch if its relentless then its a aggrestion