Should I separate?

[Leon]

Hi everyone,
I'm looking for some advice about my two robo boys, Barnum and Bailey. They are about six months old and have lived together since birth (they were part of an accidental litter I had). They have always squabbled a little, but yesterday I noticed a little scab on Bailey's rump. He is always the submissive one in fights, his smaller brother seems to initiate them. Other than the little scab (which is almost gone today) and a little fur loss around it, he seems fine, is running around quite happily and the two of them are curled up together as normal right now - they also are sleeping together still. I am obviously keeping a very close eye on them, but I am reluctant to separate them if I can avoid it, as a) I had a robo in the past who lived alone for a while and he really seemed lonely (eating less, less active) and b) I've just bought them a nice big 20 gallon tank and I don't have space for another the same, so one would have to have a smaller cage. On the other hand, of course I would rather separate them than risk serious injury.

So what do people think? Are there any other solutions that might work? (I scatter their food and they had 2 water bottles until one started to leak a few days ago - I need to replace it, but I doubt that is the immediate problem - they also have two wheels and plenty of space to hide).

Thanks for your thoughts.