my scampi and zac started fighting after being together for about 5 years and they were dad and son who use to love each other to bits. i noticed the only thing that had changed was i was taking more notice of zac cos he had been ill and it had upset the balance between them as scampi was top dog and zac thought as i was giving him more attention than normal it must mean he was now top dog so would attack scampi for no reason, and the fights were really bad, at one point my mum and i had to hold zac and scampi on the floor for over an hour and a half so they couldnt shake each other as we couldnt get them to let go of each other, we put them in the shower but they didnt let go , the vet said if that didnt work grab zacs er how should i say this? er dog dangly bits
but that didnt work so he said pinch his nose but that didnt work, so we had to just hold them untill they got tired. the fighting went on for months and we had to keep them apart, untill i noticed i had given zac the wrong message of being top dog so i made a point of stroking scampi on my lap and turning zac away, feeding scampi first and making zac wait and things like that untill i saw things go back to how they use to be between them, it was hard but it did work so the one who has had the op give him less time and the girl more of your time and see what happens. good luck.