I have a 4 inch Oscar and have just got a 2 inch Oscar to be its friend and the bigger one is chasing it around, will it ever stop? or should I get rid of the new addition?

i had lost two of my oscar with that size difference.
don't let the big one starve for death or else you will
find the smaller one missing, tail protruding the mouth
of the bigger o.

my looks good not aggressive at all. and move slowly but if I go near the tank they will get excited when they are fed, they are super fast alert even extreme when feeder fish are fed, they were mix with other fish, I felt that Oscar are Aggressive while one met the other, when there's more fish same or differences type they turn out ok, provided they have enough space in the tank, they are territorial.
My tank is so overstocked, will be more overstocked when they grow
planning on large aquarium now. one tank with 1 fish is just too boring LOL

Ive had this problem with oscars fighting and still have. driving me mad