u/Friendly-Pen-7170

My gerbils de Clanned. I split the cage. Went on a weekend away that had been planned all years. Watched for a couple days before I went and no sign of them getting to eachother. Come back and ones been murdered. The other is only 1 years old. You can see my previous post on my profile of them fighting. I just want people's opinion on where to go from here. Is keeping the one on its own the best or do I need to find a new clan mate for him? Completely reset the cage and introduce barrieredbat first? Then maybe in play pen together.