Your lucky to have them fall in order like that. My group don't care on size. I have small dats strike my biggest without thinking twice and he’s a lot bigger then them. Your pike is probably the real alpha and that’s probably why my small guys do what they do cause my pikes rule them.The big one is the clear alpha of the group and the others don’t want to challenge him, so he doesn’t have to prove himself. Once in a while my crenicichla venezuela shoos them away but they don’t want any part of him and every other fish jusy minds their own business.