In my 34 gallon tank I have 4 green tiger barbs, 3 tiger barbs a dwarf gourami, and a pinapple sword tail. They all get along pretty well. The barbs chase eachother around at times and sometimes the swordtail swims lie he's schooling with the barbs, but I have yet to see any harasment of the gourami. Granted my tank has only been running for 5 months.