Cute thing my tetras are doing

[Durbkat]

My 3 tetras, 2 long finned and a regular black tetra are swimming in a line by size. With the biggest long finned black tetra in front the regular black tetra which is the next biggest and the small long finned black tetra in the back. I just thought it was kinda funny how they just started following each other and ended up by size order. Anyone else have had this happen?

 

[Durbkat]

Never mind I think they are bully my biggest tetra because when I didn't see him with the group I found him at the top of the tank next to the heater on his side breathing heavily. So just as I put the fish net in their to fish him out and put him in a holding tank he started swimmin around again. Is he stressed from being chased and are they doing this to him since they haveen't been fed yet?