Kribs will come out more if they have a dither fish.... but unfortunaltely I don't see your tank as having room for any. And they are very territorial, expecially when they are mating. I had a 20G with 6 tiger barbs and they tormented the tiger barbs and the tiger barbs ate the babies. *sigh* I was going to upgrade but ended up loosing Mama and gave up on it. I think I would have had better success with a bigger tank. It was cute when they would take the babies to explore the tank.
I think other good dither fish are danios (but again, you would need a bigger tank).
Edit: I see slipitysmooth has a 29G. I think that is a perfect size for a mating pair and a school of dithers.
I wonder if planting (real or fake) the tank and giving them lots of places to hide would make them feel more comfortable to come out and play.
Edit 2: LOL, this is old, I see you have moved on anyway.
