Observing some odd behavior. . . but everything is still very new to me so let me know if this is normal.

55 gal tank, 48x21x13. I started off with 6 barbs, 6 tetras, and 2 corydoras.

The barbs schooled pretty closely together but were very aggressive and nippy at the cories. So I added 4 more and within 24 hours all was pretty peaceful in the tank.

However, when i came downstairs after the over night in the tank, the barbs had stopped schooling. Everything seems healthy and happy, but they were spread out all over the tank. I have witness a few nippy fights among themselves (I assume figuring out the leader of the pack). They still school together some when spooked by me walking by, but most of the day they continue to spread out all over the tank?

Any thoughts?