That is true Brian

But the black that I posted lost a yolk sack just couple days before the picture was made.
On the first picture that you posted the Arowana looks for me more like silver not black... 
I never had small Aro with yolk sack. My Black Aro had 5-6in when they arrived to my place. But I have silver Arowana with yolk sack when I was in Poland (7 years ago), and he looks similar with pictures that I posted and both your photos.
It is really confuse for me

))
Are you sure that on the first picture is a Black Arowana ?