rat fight after 6 months

Question
hi there,
Apologies for the essay....
i wanted to check something:
i have two un-neutered male rats (5-6months old) one's a white/grey hooded dumbo rex (floyd) and the other a normal black/charcoal hooded dumbo (Junai), we feed them on "supreme science selective" all-in-one dry rat food with daily fresh veggies and bits of egg/cooked meat, normally they're lovely rats floyd the rex being the bigger of the two was always the dominant, often power grooming junai etc, and junai the black hooded, has always been a bit more skittish and submissive though still friendly, tending to slink around the edges of a room hwne out and not being too keen to take food from the hand (hence we named him after a ninja character in a japanese film). although raised to gether and from the same parents they are from different litters (though we're not sure as they're rescue rats), as we understand it floyd was hand reared as his parents died (?) we got the rats when floyd was approx 6 weeks old and have kept them in a large (cage with many toys and furnishings in, we let them out for several hours each day and although they have always play fought it's never been serious lasting a matter of seconds with no injuries. as time has passed they have both become extremely tame, coming when called and climbing all over us, wrestling with us, grooming us etc.
However, i got up today to find the cage an absolute wreck and the rats running all over the place, i thought maybe they were just hyper (i over slept)so i let them out however when i picked floyd up i noticed he was more keen than usual to be stroked and was far more subdued, once i'd checked them both as we do when we get them out and found nothing wrong with them, i was putting junai onto our sofa and he jumped from my hand to the sofa landing on floyd. from there on he kept chasing floyd, being all hunched up and fluffing his coat. normally when they fight floyd does this kind of flying kick at junai and the chase each other a bit then get on with rattyness, this time however junai just chased floyd around and around. floyd seemed quite nervous (if you know what i mean) so i picked him up and put him on a window sill they like to perch on to let them be separate for a while thinking maybe they just needed some exercise and time apart, however junai after 'looking' around the room consatntly for a good 5-10 mins found floyd and cornered him walking backwards into him after a 2-3 mintue standing stare out, floyd was squeaking so i went over they completely disregarded me and fell on each other falling off the window sill in the process, when i picked them up floyd had a cut on his belly that bled enough to colour some of his fur but was not still bleeding by the time i'd called him to me, and junai has been surprisingly bold ever since seemingly looking for floyd.
as i write i've put floyd in the cage with the doors shut and left junai out but floyds still hiding and junai's still trying to attack floyd. Normally i'd let them sort it out by themselves, i hate to sound neurotic, i have had 4 female rats before and a menagerie of pets from dogs, ferrets, rabbits, siberian hamsters etc, but the sudden change in behaviour and floyd's apparent shell shock behaviour has me worried.
Finally and i think this may be the crux of the problem, junai has been having respitory problems for which he's on anti-biotics, could it be he's just stressed and lashing out at floyd's power grooming ways? or perhaps it's because junai's a bit older than floyd he's reached full maturity and grown a pair, as it were?  i ask the latter because when we first got them, junai was the dominant and only when they'd grown a bit did floyd take over. so i dont know whether to neuter, surgically or temporarily via chemicals, leave them to man it out or what
i hope you can find the time to plow through this and even reply, in the mean time i'll be checking with our vet as well as i need to pick up said anti-biotics this pm (GMT) and will leave floyd in the cage to give them both separate time
Thanks for reading this and thanks in advance if you can find the time to reply.

Chris

C D Tucker

Answer
they've hit puberty and obviously you have a personality clash. My suggestion is to have both of them neutered and they'll be able to continue to live together just fine again, however until you take the testosterone out of the picture, you're going to continue to have issues.