[sashajade]

i had the same problem between scampi and his son zac.
scampi was top dog , zac got ill and i was giving more attention to zac than normal and zac then thought he was top dog so started attacking scampi, the fights were very bad though and they would not part, one time my mum and i had to hold them over an hour still attached to each other so they didnt shake each other and really do some damage.
i started to show scampi more attention and fed, stroked and put scampi before zac, if zac came to me i would have to push him away and pick scampi up, this went on for months, it was so bad they couldnt be in the same room.
after months of treating zac different and putting scampi first in everything it all stopped and they got on again.
you have to show the other which one of the dogs is the top dog after you, fed the top dog first, stroke it first, make the other wait till the top dog goes through the door first, if both get on your lap put the other dog down and keep the top dog on your lap.
if that doesnt work the vet can give the under dog a hormone injection, my sister did this with her dog and it worked. try to think when it all started, if something had happened, if one had been ill things like that, there is normaly a reason for why it started.good luck.