Im setting up a 720 l oscar tank soon, but i don`t know what tankmates im gona buy.
I will buy some other south american cichlid`s .
What about Blue acara? Will they grow as fast as the oscars?

welcome to OFL

I've got a couple of Blue Acara, mine are still quite young, one is around 3 inches, the other one maybe four. The growth rate doesn't seem to be as fast as the Oscar. If you are buying Oscars as juveniles, let's say around 2 inches, get your blue acara at around 3 inches. I think by the time the Oscars get quite big, blue acara will be out of danger from being eaten