Thanks all.
White clouds are really cheap over here they were originally .08 a piece but now they are .12 a piece. But this is usually what i get to do my feeder fish feeding with. I plan on getting a 180gallon or bigger but not much luck is coming my way. I know the tank will be too small for the arowana(s) but i plan to get the tank ready before they outgrow the 12" mark.
I would deff go with blacks. If you wanna keep them in that tank for a while. They don't get quite as big as silvers, and in my opinion look way cooler. Problem is they are about 100$ more. have you considered putting some discus with him? I have heard mixed things about it, but that's what I'm planning on doing and from the pics I've seen of that it looks really nice.
if you want JUST an aro, a lei or jar would be your best bet, IMO, but if you want tankmates, I would go w/ a black, even though jar/lei don't always need to be by themselves.