Roseline sharks do well, or did in my tank. The more you get, the calmer the are usually. I had 40-50 at one time. I know you can't fit that many in there, but add more, it will be worth it. Also, get some of the green ones. Different color for the tank, but the tiger barbs all get along, no racism lol.
~30 Rummy-nose Tetras, ~30 Balloon Lamp-eye Tetras, 2 Bristlenose Plecos, 4 German Blue Rams, 1 Rainbow Shark ~15 Amano Shrimp, 8 Roseline Sharks, 3 Clown Loaches, 2 SAEs