What about a zonatus and a few male convicts?You could probably keep a dozen firemouth in a 125, with a big group of swords and something for a centerpiece.
Something like a melanura or one of the more passive vieja- maybe one that’s a jerk.
Orange swords, firemouths and a syn, argentae or regani would be my choice.
I’d say Pearsei but most would say they outgrow a 125