Schooling behaviour question

[swozzie]

I have 4 x Red Line Torpedo Barbs. They were in a tank with 1 Rainbow Shark who constantly chased them (and did some minor fin damage) so I have moved him. Since then, the biggest of the barbs has started behaving differently to the other 3.

When they are just schooling about, he is constantly trying to nudge them. It's doesn't look aggresive and they don't seem to mind, they just dart away an inch or so then carry on schooling about. Is this because he is the biggest and is asserting some authority over them or do you think it's a male/female thing?

 

[Maillis]

Most fish, even shoaling/schooling fish exhibit a pecking order. The one that's nudging is probably just dominate, if he doesn't seem to be hurting anyone I wouldn't worry about it.

 

[vega]

For proper schooling, the size of the group should be >6 fish,of course provided your tank size allow.