Silver How Can I Stop My Silver Arowana From Bitting The Smaller Silver Arowana?

How can i stop my silver arowana from bitting the smaller silver arowana? - silver

My Silver Arowana is stupid to bite each other and the smaller it looks very bad condition. Two Silver Arowana is a difference in the lot size. both have almost around the same size. How can I avoid the biggest small bitting? No desire to die.