Normal Behavior when tallying unsullied fish?

I have had two Black Ruby Barbs (1 male 1 female) surrounded by my tank for 2 weeks, and they have seemed fine satisfactory.

Today, i added 2 red rainbow fish. I think they are young as they are not showing much red and are mostly gold.

since i added these fish, the masculine barb has been chasing them like cracked. After a while he had stopped chasing them quite so much, but i am worried about fin nip etc.

will the rainbow fish be fine?
Could I save two feminine bettas together...
Answers:    Unfortunatelly all fish are different. Barbs tend to be territorial so I would give them a few days to settle down. Let everyone get aquainted.
What type of Fish go ably next to blood copycat, And Others?   Having two filter on my freshwater reservoir? Dirty hose 10 pts. best answer?   What will I involve for a 10 gallon fish reservoir?   I'm thinking almost setting up a Sanctuary within my house for the Beta?