u/Weak_Association591

So yesterday, one of my gerbils decided to gun for my two other gerbils, resulting in one getting many very nasty marks on his tail and drawing alot of blood. I have removed the agressor from the cage and now holding him in a carry case/playpen until i get a new cage tmr, but i don't know what to do with him. I can't keep him alone as gerbils don't live alone, and i don't know whether to do the split tank method with a new gerbil with him. I don't really want to give up this gerbil, as he is very social to humans and is very well loved in my family, but i don't want his quality of life to tank due to the declanning. What should i do in this situation?