Fish bully?

[potterboy1]

Do fish bully new fish? When I first started buying fish I got 2 Platys(they seemed to get along fine) recently 1 died and I replaced it last night but now my original Platy seems to chase the new addition around and try to ram it. Is this normal? Are they just playing tag? Hopefully it won't last long because the new fish seems to hang out as far away from the original Platy as it can. Also I believe they are both female.
Thanks
Mike

10g tank
2 Platys
3 neons

 

[Rbishop]

Yes, they do normally establish a pecking order and set up territories, in addition you can have male/female issues.