Fish co-existent help?

Hi. For a few weeks now, I have problems with my fish. The tanks is a 60 gallon tank. I have 3 bala sharks, 5 tiger barbs, 14 neon tetras, and a pleco. When I put the tiger barbs in the tanks with the others, the tiger barbs would always chase the bala sharks and the bala sharks would just run away; sometimes the tiger barbs would chase the tetras but would usually chase the balas. Is there any way that i can manipulate the tank into a better environment for both fish, to allow them to co-exist without fighting? This all happened the first few days I added the tiger barbs. Before that, it was peaceful. Right after those few days, I have separated the barbs and put them into a 10 gallon tank. Do I need to put more plants in? I have about 5 bamboo plants and 2 other kinds of plants. I apologize if I sound confusing. Let me know if there needs to be any more clarification and/or more info.