Male gerbils fighting? - Please help

[edamcheesenred]

Hey, I'm new to this forum but I have a few questions about my gerbils.

I have three male gerbils - Biscuit, Caramel and Mint. We got them from a rescue centre so none of the ages were known, only guessed. 
Biscuit is believed to be the father of the other two, and is a brown/dark tan colour. I know he is getting older now because his coat has been getting a lot lighter the last few months. (Biscuit is also certainly a lot bigger than both Caramel and Mint.)
Caramel is a tan coloured gerbil with a white belly. He is very active and healthy.
Mint is grey/white and we have recently discovered that he has a tumour on his scent gland. The vet inspected him and told us that she was not going to do surgery as he is so small and he was not in any pain or discomfort. She also recommended that we don't put him down because he was still living a happy life and had no problem, which I understood. So we took him home and just made sure that we kept a close eye on him. It's been month or so now and I have come home to blood on the bedding a few times now and I just assumed that he had caught it on something.
However, it's not Mint that I'm worried about right now, its the other two, Caramel and Biscuit.
Recently, Biscuit has been aggressive towards the other gerbils, mostly Caramel. Biscuit has had sudden bursts of chasing Caramel around their tank, with his fur raised. Also, Biscuit mostly sleeps slightly away from the other two. He pushes in front when I scatter their food, and will always throw the other gerbils out of the way to reach the water. 
Mint tends to sleep more often now and is slightly slower than Biscuit and Caramel. He tends to stay out of Biscuit's way, but is still happy to be near Caramel and sleep with him, he just avoids Biscuit.
I know this could also be a dominance issue, but they have only started it up in the last few weeks/month. I have also researched it a bit but fighting is less common in male gerbils.
I'm unsure what to do next, because I don't want to separate them as they are (supposedly) family.
Do I punish Biscuit?
Do I separate him (permanently or temporarily)?
Do I just wait (as I am expecting Biscuit to pass away before the others)?

Thanks for any help I can get, I am grateful for it all. x

[jgl]

Hi,
You should definitely have some gardening gloves on hand to separate them if need be an additional cage setup might also be a good idea. You usually want to separate the one being bullied when fighting happens because that one will be easier to pair up with another gerbil, but it sounds like biscuit is not doing well with either of them so if it came down to it I would take him out.
You should try to prevent the fight though, you could put them into a split and see if reintroducing helps. Other than that I don't have much experience with preventing fights, maybe someone with more experience can help you.

[catnut]

I don't have a lot of experience, but I would temp. put Biscuit by himself and see how he does. Maybe as he is getting older, he needs more space or just doesn't want the other two around anymore. It is always better as when you see signs, you never know when they will escalate to something worse, I had two brothers and once they reached 2, they had issues with each other so I had to separate them. I think it was due to one having a tumour and he smelled different so his brother didn't recognize him or just didn't like his new smell. I've had lone gerbils, I have two at present and they can quite well by themselves with extra attention.

Tammy

[edamcheesenred]

Ok. Thanks guys. I think I will separate Biscuit as that seems like the best option. x