Guppy Killed Platys

[Suresh]

I had 3 guppy (1 male and 2 female) and 3 platys (2 males and 1 female). Initially one of male platy was harassing a female guppy constantly and keep on going near it. after some time it seemed the female got very stressed and start attacking platy. but platy never stopped going near guppy. 
after some point of time the guppies keep on attacking all platys. because of that 2 platys are killed with bruises in their body. though the platy that caused this problem is still safe.
i thought this will get used to it but i lost 2 platys.
can anyone tell is this strange or i have very aggressive guppys?
 

 

[lrhodes]

I personally have never heard of guppies being aggressive toward anything...
 
Hmm... Maybe someone has had a similar story. Are there any other fish in the tank that could have killed them?

 

[PrairieSunflower]

No, I've kept both together with not even a fin nipped. 
 
Can you tell us more about your tank, is it cycled, ammonia, nitrite, nitrate, tank size, how long you've had the fish, etc.
 
One thing that is already wrong is your ratio of males to females... and it makes me wonder if these fish are in very close quarters in order to be bickering so much.
 
Could you post photos of your fish as well.

Could your guppy be a mosquito fish?

 

[ncguppy830]

Its not uncommon for livebearers to be aggressive, Your ratio with 2 males one female platy might have caused aggression issues, given there should be 2 females to one male. Do you know if the female platy got killed? This could help.