Sixline wrasse in my 28 gallon aio. Added him last. All was well for 6 months. No aggression, nothing.
My tailspot blenny quit eating and died. Replaced him with a similar sized starry blenny and that wrasse lost its mind.
Not only did it bully the blenny back into a hole any time it tried to come out, but it started trying to tear into my clowns time and again and they weren't having any of it.
Had to take everything out of the tank to catch the little jerk, he got to spend a few days in a timeout acclimation box.
Exactly 2 seconds after I put him back in he started up again. Earned a one way ticket back to the LFS.
Got a yellow coris wrasse now and love it. Takes care of it's wrasse business and doesn't bother anyone.