I don't think a lone redbelly will ever eat a mouse, unless you raise him to be really agressive and nasty (which I doubt can be done intentionally).
I noticed that my reds usually do not start attacking and eating a large food item on their own: they all close in on it, and one after the other chases it for a while, trying to bite and injure it, so it gets weakened. And the frenzy needed to take down a larger prey only starts when the prey is wounded and weakened... My reds usually are pretty nervous hunters, and a slight movement from a feeder is often enough to drive them off for a while, although what they lack in pure bloodthirsty-ness, they compensate with perseverance (again, these are my observations!!!)
This is about feeders: I usually give them shrimp and smelt, offering small pieces at a time, to minimize the frenzy and the risk of them injuring each other (perhaps not as cool, but I don't want my reds to injure each other unnecessarily).
I feed mine once a day, usually between 9 and 10 pm. When they were still babies, I fed them 3 times a day, so they could grow fast, but I gradually reduced that when they grew larger.
Oh, and one more tip: next time you want to post a question, select the "New Topic"-button, instead of the "New Poll"-button