Tiger Barbs you got to love them but picking companions for them is always tough. When kept in groups of 7 or more they may focus most of their boisterous beheviour on each other but no guarentees. I have seen the temperament of the group change with the adition or subtraction of one more or less tiger. You get a group of 7 or 8 no probelms, getting along with everything in the tank, you add a couple and they all turn nippy, peer pressure I guess.
I have kept them with a Red Tail Black Shark, Clown Barbs, Pictus Cats, Flying Barbs, Ruby Barbs, Pearl Danios, South American Bumblebee Cats, Kribensis, Melon Barbs, Arulius Barbs, Kissing Gouramis, Spotted Rhapeal Catfish, Albino Corys, and various Plecos. Before I hear from the overstocking police this was obviously not all at the same time or in the same tank. No incidents with any of these species.
I would avoid any long finned, trailing finned or slow fish. I have seen them damage the long threaded fins on Angels and Gouramis, and shred Betas and Guppies. I also seen an unfortunate incident wher the LFS but the ferious looking Dragon Gobies in with Tiger Barbs. The Gobies are actually very peaceful and didn't fare well at all.
Good luck they're great fun just a little frustrating to find tankmates for.