If i have a b from when it was small?

if i have a b in my fish tank from when it was 3.5 inches long, and all i feed it is dried krill, frozen brine shrimp (but obviusly thawed out), and nightcrawlers. is it possible for him to not eat other fish because he wasnt raised on them becasue i want to keep him but not if he will end up eating my fish. right now my fish are cichlids and between 2.5 and 3.5 inches long. the b is about 4 inches. please answer and help!!!!