We've had two male gerbils, who are brothers, for about 18 months and they've always been perfectly happy together...until recently. One night, I found them both covered in blood - they had obviously been fighting and managed to cut/bite/scratch each other quite badly. Anyway we washed them off and put them back and after a few hours of keeping apart they went back to being best buddies again, cuddling up together. Then a couple of nights ago we found one of them was cut again....we don't really want to have to separate them as they probably don't have much life left, and we don't want to have to get another gerbilarium. On the other hand, I don't want them to fight to the death...anyone had similar?
Oh stranded, I'm so sorry to hear this. In the past I've had 2 pairs of female gerbils, a trio of 3 brothers and a lone foster gerbil. In my experience, once companions have fallen out so badly that blood has been drawn, it's best to separate them because they'll never go back to the same kind of "trust" again. I haven't had gerbils for about 15 years now though, so I'm willing to be corrected by someone with more up to date knowledge.
I've had gerbils live to nearly 5, but also one who died suddenly at about 2, so it's hard to tell how long they will live. They are happiest in pairs (trios okay for boys) but I fostered as solo male who seemed content enough in his tank until the end of his life. You could get two smaller ones side by side so they would still hear, smell and sometimes see each other, but not be able to make physical contact. Good luck!