Wrasse agression issue

[Marinelifelover]

Hey guys,
I have a Melanrus wrasse who has previously been housed with Mandrin Gobies however the last few months its been just him and a pair of clowns in the tank and he has started to feel like its his tank so when I added a new Mandrin about a week ago I noticed it was hiding during the day assumed he was adjusting but then saw him out in the morning when the lights came on and the wrasse went right for him repeatedly. I was finally able to capture the wrasse and put him in a QT tank in a breeder box but im worried about just waiting and re releasing after a week or two. Is there anything else I can do as well or try instead to make sure he adjusts to accept this new mandrin? I have thought about the fact that before he was in with a similar sized hippo and coral beauty when he never minded the mandrin and am thinking mabye adding him back with a more like sized competitor so to say he wont just assume its his territory to take back over.
Thanks in advance I appreciate everyone's time.
Victor