I had a Jardini around 10" and some Orino around 7" in a 210G - the Jardini pinned the Orino into a 2' cube up the side of the tank and kept them there.
Try it if you like but you'll be lucky to be keeping it that way - my advice would be find an alternative, If silver arowana's are not for you and you prefer the thicker bodied but don't want to pay extreme money then why not consider a green arowana or a Banjar arowana?