i had 1 and it was relatively peacefull....till my puffers attacked it and it died.
but they run about $8 at the LFS...they're rarer then they typical yellow tail.
definitely a Beaugregory. I have had one in my 75 FOWLR for about a year. VERY aggressive and territorial. I have another small Brazilian damsel in the tank that has become buddies with the beaugregory and they rule the tank together.