u want a killer fish?? well I have a good one for ya... get a Red Devil... but u'll have to keep it in its own tank or it will kill & eat all ur other fish, including ur Oscar...

All the fish I have r killers

I have:
a Tiger Oscar named Oscar
a Jack Dempsey named Jack
& a Red Devil named Mango

Mango has long skinny black teeth, he can bite a large feeder goldfish in half!!

& if u want ur red devil to become super agressive, all u have to do is put rocks in its tank.. it will pile them against the front of the tank & make its home & every time u walk infront of the tank it will try to eat u... which is kinda funny...