Usually time will calm them down. But wat i do is i get a separater glass for any type of fish. They see each other and fight. they try fighting eah other but can't. Once they sort of ignore each other take out the glass. And if they fight again put the glass back on. Easy as that. That is how i train my fish. 
know my 6inch oscar will leave guppies alone and my jar will leave my silver alone 
know my 6inch oscar will leave guppies alone and my jar will leave my silver alone 
you smoking weed?
