Yes, they will get along together. My concern is the growth rates. I'm unfamiliar with the growth rate of bala's, but Oscars grow very, very fast, and the 2" size of yours is not part of the equation - you must think in terms of an adult 12" Oscar. Back to my concern - if the bala's are also babies, and the Oscar seriously outgrows the balas, then they may become Oscar food.