I once tried a maroon, things didn't go well.... She was fine on her own for months, then my LFS
got 4 juveniles in. I decided to buy her a mate so went down and picked the smallest of the 4.
Got home and put it in with the existing larger fish, which instantly attacked it in the most savage way. It ripped all it's fins off and proceeded to grip the new addition in its mouth, ramming it into the glass and rocks.
Needless to say it was dead in under 5 minutes and the larger one banished to the LFS
. The whole episode traumatised my wife to the point that she nearly made me give up the hobby. So I'll never entertain maroons again.