Yea there prlly just now entering their teen stage, which imo is when they really start nipping at eachother. I know size doesn't determine sexual maturity but any rbp I've seen breed (not my own) has always been 6"+
They been nipping each other a lot. I see they are getting really comfortable tho.. I turn the light on regularly on a time schedule and they are really active. Just I covered about 65% of the light tho lol