I have that mix right now in my 300 gal tank along with a pacu and large type silver dollars, the balas (4) get along real well with tinfoils (4) that I have, they dont school, (swim) together but they hang out together, they feel more secure in numbers when the giant pacu chases the silver dollars around hehehe. My tinfoils are timid compared to the other fish including the balas and because of this they are less aggresive at feeding time and get a little less food and grow less then the balas and the other fish, to sort of fix this I open many lids and feed from different points of the tanks now so that all get a more even amount.