personally I wouldn't hesitate to feed them live even when they are small. In fact i think that's the time they put on the best show as larger p's just finish feeders off in a bite or two. As long as your feeders are healthy and are not a type of fish that can fight back i cannot forsee any problems. When I had red bellies I fed them live (as well as many other non live items for a varied diet) from the time they where the size of a quarter to maturity. Others may have a different view but in my experience they are very capable predators.I have been hesitent to feed them live fish this early. is it a good idea to start feedind them live fish this early. they love bloodworms also.