The Uaru is too mild temper for the stocklist of that tank IMO. Even if it don't get killed I'm afraid it might not be able to compete for foods.
Keeping large aggressive fishes is all about trial and errors, one combo might work for one person but not the next. And another thing is they'll get along fine but next morning you could wake up to find dead fishes from aggression. I just had a male Dovii turned physco and killed my male Red Mota who was slightly bigger. Thing is they have been in same tank for almost 3 months now.