the barb's may work but something very important if you are serious about trying all of those in a 120 together is to have an ass load of potential territory decoration's. lots and lots of rocks cave's wood, flower pots etc. thats alot of territory needed for fish that get at the smallest 6 inchs' I can tell ya one thing, there wont be much cruising going on, your fish will be staying in one area at all times or they will show some torn fin's and missing scales