Agressive Unicorn???

From all I have read unicorn tang are very docile fish. So when I added a pair of hencious butterfly fish (not sure of spelling) I watched them for a hour or so and they were doing fine so I went off to bed. Unicorn tang was hangin with them, swimming around like normal, (he is a very active fish) and not paying much attention to them. Next morning I was down one butterfly, and the other looked fine. I watched again and the unicorn was minding his own business. I have heard reports that once every great while a coral banded shrimp will attack fish. being it was night time when this happened, and they are nocturnal I started to blame him. so I pulled him out and a few months later added a yellow tang. The unicorn, still smaller than the tang went mid-evil on his ass. I pulled the unicorn and put him in my quarentine tank. Now what do I do with him. He is one of my favorite fish, and I have another tank, (120 gallon) that has a clown with anenome, a very big sailfin, a smaller violet tang, and a pajama cardinal. this tank has been very peaceful and all fish are happy.

My options are get rid of the unicorn,

Put him in the other aquarium with my well established tank and see how he gets along

put my new fish in the other aquarium (yellow tang and small yellow tail tang) Being the same body style my sailfin may not like him. then make that a fish only tank

or move all my well established fish into the smaller tank (90 gallon) and make my larger tank into a more fish only tank and add the puffer I have been wanting and a couple triggers I have had my eye on.

What do you think??

 

bump cause I'm not sure about a Unicorn Tang

 

can you put your unicorn tang temporarily in the other tank. let the yellow tang get established and then return the unicorn tang to the original tank? this could alleviate the territory issues.

 

also, how long after the initial fighting did you pull the fish. sometimes with tangs, they will fight at first to determine dominance and then grow to tolerate each other. when i added my powder blue to a tank already dominated by a dejardini sailfin, they fought viciously the first night. after the first night, they tolerate each other with very little fighting.

 

let the unicorn sit a few days in QT. how big is it? give the new fish some time to acclimate and adding hte unicorn back in will be ok.