Stocking a 698 gallon tank with D.campbelli

Hi Guys!

I just ordered a 698g tank with a 100g sump, dimensions of the tank are 118x43x31 (LxWxH).
How many campbelli would be good to put in it if I plan to keep the group for life? 10?

I also plan to add one asian arowana once I saved up some money again...

Feels good to finally be cured of my "Small Tank Syndrome"

Just to clarify I'm wondering how many I should have, so the tank doesn't look completely packed nor empty when they get big/adults.
Plan is to have minimal decoration, maybe just one large piece of wood with some Anubias on and some long Vallisneria in the back.