Hi guys I'm new to this site, and had a few questions. I curently have a 120G setup with two Pangasius sanitwongsei, Man can these guys eat

. one at aprox 20" and the other aporx 24"(pics will come soon). The question i have is i am interested in setting up a new tank for about 5-6 small Pangasius hypophthalmus and was wondering if anyone has any hints or tips on what stye of tank to setup and weather or not to do a river tank? all comments welcome.
Thank you
Sean